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 A373280 #11 May 30 2024 09:51:58
%S A373280 1,4,16,65,256,1024,4096,16388,65536,262144,1048576,4194320,16777216,
%T A373280 67108864,268435456,1073741889,4294967296,17179869184,68719476736,
%U A373280 274877907200,1099511627776,4398046511104,17592186044416,70368744178688,281474976710656,1125899906842624
%N A373280 Expansion of Sum_{k>=0} x^(4^k) / (1 - 4*x^(4^k)).
%H A373280 Seiichi Manyama, <a href="/A373280/b373280.txt">Table of n, a(n) for n = 1..1000</a>
%F A373280 G.f. A(x) satisfies A(x) = x/(1 - 4*x) + A(x^4).
%F A373280 If n == 0 (mod 4), a(n) = 4^n + a(n/4) otherwise a(n) = 4^n.
%Y A373280 Cf. A187767, A373279, A373281, A373282, A373283.
%Y A373280 Cf. A000302, A115362.
%K A373280 nonn
%O A373280 1,2
%A A373280 _Seiichi Manyama_, May 30 2024