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 A066002 #24 Dec 04 2024 15:40:00
%S A066002 1,6,9,9,18,27,27,36,36,36,36,45,45,36,54,63,54,72,72,63,72,81,63,72,
%T A066002 90,90,99,99,90,135,117,99,126,126,135,135,126,135,135,162,171,126,
%U A066002 153,153,153,162,180,162,153,162,171,216,171,216,171,162
%N A066002 Sum of digits of 6^n.
%H A066002 Harry J. Smith, <a href="/A066002/b066002.txt">Table of n, a(n) for n = 0..1000</a>
%F A066002 a(n) = A007953(A000400(n)). - _Michel Marcus_, Nov 01 2013 [corrected by _Georg Fischer_, Dec 28 2020]
%t A066002 Table[Total[IntegerDigits[6^n]], {n, 0, 60}] (* _Vincenzo Librandi_, Oct 08 2013 *)
%o A066002 (PARI) a(n) = sumdigits(6^n); \\ _Michel Marcus_, Nov 01 2013
%Y A066002 Cf. sum of digits of k^n: A001370 (k=2), A004166 (k=3), A065713 (k=4), A066001 (k=5), this sequence (k=6), A066003(k=7), A066004 (k=8), A065999 (k=9), A066005 (k=11), A066006 (k=12), A175527 (k=13).
%Y A066002 Cf. A007953.
%K A066002 nonn,base
%O A066002 0,2
%A A066002 _N. J. A. Sloane_, Dec 11 2001