This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A067864 #21 Nov 09 2024 20:04:36 %S A067864 1,3,9,18,90 %N A067864 Numbers k such that k divides the sum of digits of 6^k. %C A067864 Conjecture: the sequence is finite, since (sum of the digits of 6^k)/k -> log_10(6)*4.5 ~ 3.50168 as k->infinity (this is also a conjecture). - _Robert Gerbicz_, May 08 2008 %C A067864 Next term, if it exists, exceeds 100000. - _Sean A. Irvine_, Apr 05 2010 %C A067864 The keyword "hard" refers to the difficulty of finding, or disproving the existence of, the next term. - _N. J. A. Sloane_, Nov 09 2024 %e A067864 a(1)=3, so 3 divides the sum of digits of 6^3 (i.e., 2 + 1 + 6 = 9). %t A067864 Select[Range[100],Mod[Total[IntegerDigits[6^#]],#]==0&] (* _Harvey P. Dale_, Nov 09 2024 *) %Y A067864 Cf. A000400, A066002, A175457, A175169, A067862, A067863. %K A067864 hard,nonn,base %O A067864 1,2 %A A067864 _Amarnath Murthy_ and _Shyam Sunder Gupta_, Feb 16 2002