Repunits whose digits in base $b$ are all $b-1$












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Positive integers whose base-$b$ representation contains only the digit $1$ are called repunits in that base. But what about positive integers whose base-$b$ representation contains only the digit $b-1$?



For instance, how would one call the base-$20$ number whose representation in that base is
$$19cdot19cdot19cdot19cdot19_{20}?$$



Is there a special name for this kind of number? I know repunits are useful in many number-theoretical contexts, but what about such numbers?










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  • 1




    $begingroup$
    You mean like 99999 in base 10?
    $endgroup$
    – qwr
    Dec 18 '18 at 17:30








  • 2




    $begingroup$
    Probably not. They can be written as $b^{k}-1.$
    $endgroup$
    – Thomas Andrews
    Dec 18 '18 at 17:30
















0












$begingroup$


Positive integers whose base-$b$ representation contains only the digit $1$ are called repunits in that base. But what about positive integers whose base-$b$ representation contains only the digit $b-1$?



For instance, how would one call the base-$20$ number whose representation in that base is
$$19cdot19cdot19cdot19cdot19_{20}?$$



Is there a special name for this kind of number? I know repunits are useful in many number-theoretical contexts, but what about such numbers?










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    You mean like 99999 in base 10?
    $endgroup$
    – qwr
    Dec 18 '18 at 17:30








  • 2




    $begingroup$
    Probably not. They can be written as $b^{k}-1.$
    $endgroup$
    – Thomas Andrews
    Dec 18 '18 at 17:30














0












0








0


1



$begingroup$


Positive integers whose base-$b$ representation contains only the digit $1$ are called repunits in that base. But what about positive integers whose base-$b$ representation contains only the digit $b-1$?



For instance, how would one call the base-$20$ number whose representation in that base is
$$19cdot19cdot19cdot19cdot19_{20}?$$



Is there a special name for this kind of number? I know repunits are useful in many number-theoretical contexts, but what about such numbers?










share|cite|improve this question









$endgroup$




Positive integers whose base-$b$ representation contains only the digit $1$ are called repunits in that base. But what about positive integers whose base-$b$ representation contains only the digit $b-1$?



For instance, how would one call the base-$20$ number whose representation in that base is
$$19cdot19cdot19cdot19cdot19_{20}?$$



Is there a special name for this kind of number? I know repunits are useful in many number-theoretical contexts, but what about such numbers?







elementary-number-theory number-systems






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asked Dec 18 '18 at 17:27









KlangenKlangen

1,69811334




1,69811334








  • 1




    $begingroup$
    You mean like 99999 in base 10?
    $endgroup$
    – qwr
    Dec 18 '18 at 17:30








  • 2




    $begingroup$
    Probably not. They can be written as $b^{k}-1.$
    $endgroup$
    – Thomas Andrews
    Dec 18 '18 at 17:30














  • 1




    $begingroup$
    You mean like 99999 in base 10?
    $endgroup$
    – qwr
    Dec 18 '18 at 17:30








  • 2




    $begingroup$
    Probably not. They can be written as $b^{k}-1.$
    $endgroup$
    – Thomas Andrews
    Dec 18 '18 at 17:30








1




1




$begingroup$
You mean like 99999 in base 10?
$endgroup$
– qwr
Dec 18 '18 at 17:30






$begingroup$
You mean like 99999 in base 10?
$endgroup$
– qwr
Dec 18 '18 at 17:30






2




2




$begingroup$
Probably not. They can be written as $b^{k}-1.$
$endgroup$
– Thomas Andrews
Dec 18 '18 at 17:30




$begingroup$
Probably not. They can be written as $b^{k}-1.$
$endgroup$
– Thomas Andrews
Dec 18 '18 at 17:30










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$begingroup$

While there is no name, to my knowledge, for the general case, they are referred to as Mersenne numbers for base 2.






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    $begingroup$

    While there is no name, to my knowledge, for the general case, they are referred to as Mersenne numbers for base 2.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      While there is no name, to my knowledge, for the general case, they are referred to as Mersenne numbers for base 2.






      share|cite|improve this answer









      $endgroup$
















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        1





        $begingroup$

        While there is no name, to my knowledge, for the general case, they are referred to as Mersenne numbers for base 2.






        share|cite|improve this answer









        $endgroup$



        While there is no name, to my knowledge, for the general case, they are referred to as Mersenne numbers for base 2.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 18 '18 at 17:38









        RJJBRJJB

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