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 A171197 #19 Jul 06 2025 10:09:56
%S A171197 1,1,15,533,36415,4624621,1108685495,513716588981,467874135168079,
%T A171197 845152554936920445,3041003426951554000167,21840734269889733272106629,
%U A171197 313415404907854466274076819391,8990640466019774671530066108827853
%N A171197 G.f. A(x) satisfies A(x) = 1/(1 - x*A(2*x)^7).
%H A171197 Seiichi Manyama, <a href="/A171197/b171197.txt">Table of n, a(n) for n = 0..79</a>
%F A171197 a(n) ~ c * 2^(n*(n-1)/2) * 7^n, where c = 0.307176924551399606223470587229647816147018... - _Vaclav Kotesovec_, Nov 03 2021
%F A171197 a(0) = 1; a(n) = 2^(n-1) * Sum_{x_1, x_2, ..., x_8>=0 and x_1+x_2+...+x_8=n-1} (1/2)^x_1 * Product_{k=1..8} a(x_k). - _Seiichi Manyama_, Jul 06 2025
%t A171197 nmax = 15; A[_] = 0; Do[A[x_] = 1/(1 - x*A[2*x]^7) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x] (* _Vaclav Kotesovec_, Nov 03 2021 *)
%o A171197 (PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=1/(1-x*subst(A, x, 2*x)^7) ); polcoeff(A, n)}
%Y A171197 Cf. A015083, A171192-A171196, A171198.
%K A171197 nonn
%O A171197 0,3
%A A171197 _Paul D. Hanna_, Dec 05 2009