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 A171203 #10 Apr 02 2025 16:09:46
%S A171203 1,4,38,708,24961,1682688,220959136,57266675520,29497077110720,
%T A171203 30294634141775360,62134850895148484608,254691311135373319017472,
%U A171203 2087196424913845641682560512,34202892422993270952623113994240,1120863025258656246362522776511881216,73460242428855296330451249854756580540416
%N A171203 G.f. satisfies: A(x) = (1 + x*A(2x))^4.
%F A171203 Self-convolution 4th power of A171202 where a(n) = A171202(n+1)/2^n for n>=0.
%t A171203 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 A171203 (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 A171203 Cf. A135868, A171200, A171201, A171202, A171204-A171211.
%K A171203 nonn
%O A171203 0,2
%A A171203 _Paul D. Hanna_, Dec 05 2009
%E A171203 a(14)-a(15) from _Stefano Spezia_, Apr 02 2025