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 A171202 #19 Jul 08 2025 07:47:02
%S A171202 1,1,8,152,5664,399376,53846016,14141384704,7330134466560,
%T A171202 7551251740344320,15510852680588984320,63626087316632048238592,
%U A171202 521607805205244557347782656,8549156556447111748331767857152,280190094729160875643888549840814080,18364219805837823940403573170370661842944
%N A171202 G.f. A(x) satisfies A(x) = 1 + x*A(2*x)^4.
%H A171202 Seiichi Manyama, <a href="/A171202/b171202.txt">Table of n, a(n) for n = 0..80</a>
%F A171202 a(0) = 1; a(n) = 2^(n-1) * Sum_{i, j, k, l>=0 and i+j+k+l=n-1} a(i) * a(j) * a(k) * a(l). - _Seiichi Manyama_, Jul 08 2025
%t A171202 terms = 16; A[_] = 0; Do[A[x_] = 1 + x*A[2x]^4 + O[x]^terms // Normal, terms]; CoefficientList[A[x], x] (* _Stefano Spezia_, Apr 02 2025 *)
%o A171202 (PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=1+x*subst(A, x, 2*x)^4); polcoeff(A, n)}
%Y A171202 Cf. A135867, A171200, A171201, A171203, A171204-A171211, A343439.
%Y A171202 Cf. A143047, A171193.
%K A171202 nonn
%O A171202 0,3
%A A171202 _Paul D. Hanna_, Dec 05 2009