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 A309678 #6 Aug 12 2019 22:38:18
%S A309678 1,2,3,4,7,10,13,16,22,28,34,40,50,60,70,80,97,114,131,148,175,202,
%T A309678 229,256,296,336,376,416,472,528,584,640,718,796,874,952,1058,1164,
%U A309678 1270,1376,1516,1656,1796,1936,2116,2296,2476,2656,2886,3116,3346,3576,3866,4156,4446,4736,5096
%N A309678 G.f. A(x) satisfies: A(x) = A(x^4) / (1 - x)^2.
%F A309678 G.f.: Product_{k>=0} 1/(1 - x^(4^k))^2.
%t A309678 nmax = 56; A[_] = 1; Do[A[x_] = A[x^4]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
%t A309678 nmax = 56; CoefficientList[Series[Product[1/(1 - x^(4^k))^2, {k, 0, Floor[Log[4, nmax]] + 1}], {x, 0, nmax}], x]
%Y A309678 Cf. A005705, A171238, A174026, A309677, A309679.
%K A309678 nonn
%O A309678 0,2
%A A309678 _Ilya Gutkovskiy_, Aug 12 2019