what proportion of positive integers have exactly N pairs of consecutive integer factors?












3












$begingroup$


This is a followon to this question, which asked for the proportion of integers that have (any) consecutive integer factors.



Now, what proportion has exactly one pair? Since every odd number is = (2*n+1), we have to reject any integer K with factors 2, n, (2n+1). It looks as though there will be some ugly formula that starts with {2,n} and disallows (2n+1) ... and , when 2^j is a factor of n, disallows 2^(j+1) as a factor of K.



So, as a followon, I'll leave the general case as well: what proportion of positive integers has exactly N pairs of consecutive factors?










share|cite|improve this question









$endgroup$












  • $begingroup$
    Clearly deserves a vote.
    $endgroup$
    – marty cohen
    Dec 14 '18 at 17:26
















3












$begingroup$


This is a followon to this question, which asked for the proportion of integers that have (any) consecutive integer factors.



Now, what proportion has exactly one pair? Since every odd number is = (2*n+1), we have to reject any integer K with factors 2, n, (2n+1). It looks as though there will be some ugly formula that starts with {2,n} and disallows (2n+1) ... and , when 2^j is a factor of n, disallows 2^(j+1) as a factor of K.



So, as a followon, I'll leave the general case as well: what proportion of positive integers has exactly N pairs of consecutive factors?










share|cite|improve this question









$endgroup$












  • $begingroup$
    Clearly deserves a vote.
    $endgroup$
    – marty cohen
    Dec 14 '18 at 17:26














3












3








3





$begingroup$


This is a followon to this question, which asked for the proportion of integers that have (any) consecutive integer factors.



Now, what proportion has exactly one pair? Since every odd number is = (2*n+1), we have to reject any integer K with factors 2, n, (2n+1). It looks as though there will be some ugly formula that starts with {2,n} and disallows (2n+1) ... and , when 2^j is a factor of n, disallows 2^(j+1) as a factor of K.



So, as a followon, I'll leave the general case as well: what proportion of positive integers has exactly N pairs of consecutive factors?










share|cite|improve this question









$endgroup$




This is a followon to this question, which asked for the proportion of integers that have (any) consecutive integer factors.



Now, what proportion has exactly one pair? Since every odd number is = (2*n+1), we have to reject any integer K with factors 2, n, (2n+1). It looks as though there will be some ugly formula that starts with {2,n} and disallows (2n+1) ... and , when 2^j is a factor of n, disallows 2^(j+1) as a factor of K.



So, as a followon, I'll leave the general case as well: what proportion of positive integers has exactly N pairs of consecutive factors?







number-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 14 '18 at 15:44









Carl WitthoftCarl Witthoft

32618




32618












  • $begingroup$
    Clearly deserves a vote.
    $endgroup$
    – marty cohen
    Dec 14 '18 at 17:26


















  • $begingroup$
    Clearly deserves a vote.
    $endgroup$
    – marty cohen
    Dec 14 '18 at 17:26
















$begingroup$
Clearly deserves a vote.
$endgroup$
– marty cohen
Dec 14 '18 at 17:26




$begingroup$
Clearly deserves a vote.
$endgroup$
– marty cohen
Dec 14 '18 at 17:26










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3039523%2fwhat-proportion-of-positive-integers-have-exactly-n-pairs-of-consecutive-integer%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3039523%2fwhat-proportion-of-positive-integers-have-exactly-n-pairs-of-consecutive-integer%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Plaza Victoria

In PowerPoint, is there a keyboard shortcut for bulleted / numbered list?

How to put 3 figures in Latex with 2 figures side by side and 1 below these side by side images but in...