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 A067509 #12 Apr 21 2020 13:52:17 %S A067509 5,390625,9765625,37252902984619140625,9094947017729282379150390625, %T A067509 227373675443232059478759765625,3552713678800500929355621337890625, %U A067509 2220446049250313080847263336181640625 %N A067509 Powers of 5 with digit sum divisible by 5. %H A067509 Robert Israel, <a href="/A067509/b067509.txt">Table of n, a(n) for n = 1..298</a> %p A067509 filter:= proc(n) convert(convert(n,base,10),`+`) mod 5 = 0 end proc: %p A067509 select(filter, [seq(5^n,n=1..100)]); # _Robert Israel_, Apr 21 2020 %Y A067509 Subsequence of A000351. %Y A067509 Cf. A067499, A067500, A067501, A067502, A067503, A067504, A067505, A067506, A067507. %K A067509 base,easy,nonn %O A067509 1,1 %A A067509 _Amarnath Murthy_, Feb 11 2002 %E A067509 More terms from _Sascha Kurz_, Mar 18 2002 %E A067509 Offset changed by _Robert Israel_, Apr 21 2020