login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Numbers k such that sum of digits of k^3 is 8. Multiples of 10 are omitted.
0

%I #14 Feb 19 2021 09:49:22

%S 2,5,8,11,101,1001,10001,100001,1000001,10000001,100000001,1000000001,

%T 10000000001,100000000001,1000000000001,10000000000001,

%U 100000000000001,1000000000000001,10000000000000001,100000000000000001,1000000000000000001,10000000000000000001

%N Numbers k such that sum of digits of k^3 is 8. Multiples of 10 are omitted.

%C All numbers of form 10..01 are eligible. Are there larger terms of other forms?

%C All terms up to 10^20 are of this form, except for 2, 5 and 8. - _Max Alekseyev_, Feb 11 2008

%C Numbers k such that k > 1 and sum of digits of k^3 is less than 9. Multiples of 10 are omitted. - _Farideh Firoozbakht_, Oct 18 2013

%e 2^3=8, 5^3=125, 8^3=512, 11^3=1331, 101^3=1030301, 1001^3=1003003001, 10001^3=1000300030001.

%t Do[If[Total[IntegerDigits[m^3]]==8&&Mod[m,10]>0,Print[m]],{m,100000}]

%o (PARI) isok(k) = (k % 10) && (sumdigits(k^3) == 8); \\ _Michel Marcus_, Feb 19 2021

%K nonn,base

%O 1,1

%A _Zak Seidov_, Feb 11 2008

%E a(9) onwards from _Max Alekseyev_, Feb 11 2008