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 A256135 #31 Feb 28 2017 22:47:14
%S A256135 1,5,5,25,5,25,25,125,5,25,25,125,25,125,125,625,5,25,25,125,25,125,
%T A256135 125,625,25,125,125,625,125,625,625,3125,5,25,25,125,25,125,125,625,
%U A256135 25,125,125,625,125,625,625,3125,25,125,125,625,125,625,625,3125,125,625,625,3125,625,3125,3125,15625
%N A256135 a(n) = 5^A000120(n).
%C A256135 Also, a row of the square array A256140.
%C A256135 It appears that when A151780 is regarded as a triangle in which the row lengths are the powers of 2, this is what the rows converge to.
%F A256135 a(n) = A000351(A000120(n)). - _Michel Marcus_, Mar 21 2015
%F A256135 G.f.: Product_{k>=0} (1 + 5*x^(2^k)). - _Ilya Gutkovskiy_, Feb 28 2017
%e A256135 Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
%e A256135 1;
%e A256135 5;
%e A256135 5, 25;
%e A256135 5, 25, 25, 125;
%e A256135 5, 25, 25, 125, 25, 125, 125, 625;
%e A256135 ...
%t A256135 5^# & /@ Nest[Join[#, # + 1] &, {0}, 6] (* _Michael De Vlieger_, Mar 20 2015, after _IWABUCHI Yu(u)ki_ at a000120 *)
%o A256135 (PARI) a(n) = 5^hammingweight(n); \\ _Michel Marcus_, Mar 21 2015
%Y A256135 Cf. A000120, A001316, A048883, A102376, A130667, A151780, A256140, A256141.
%K A256135 nonn
%O A256135 0,2
%A A256135 _Omar E. Pol_, Mar 19 2015
%E A256135 More terms from _Michael De Vlieger_, Mar 20 2015