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 A371517 #16 Mar 27 2024 08:54:04
%S A371517 1,4,26,188,1459,11892,100444,871528,7722557,69590628,635807180,
%T A371517 5876094308,54836925779,516029817620,4891147100886,46653935716492,
%U A371517 447490869463145,4313492172957396,41763413498670702,405968522259130636,3960526930400038404
%N A371517 G.f. A(x) satisfies A(x) = (1 + x*A(x) / (1-x))^4.
%F A371517 a(n) = 4 * Sum_{k=0..n} binomial(n-1,n-k) * binomial(4*k+3,k)/(3*k+4) = Sum_{k=0..n} binomial(n-1,n-k) * binomial(4*k+4,k)/(k+1).
%F A371517 G.f.: A(x) = B(x)^4 where B(x) is the g.f. of A349331.
%o A371517 (PARI) a(n) = 4*sum(k=0, n, binomial(n-1, n-k)*binomial(4*k+3, k)/(3*k+4));
%Y A371517 Cf. A045868, A371516, A371520, A371521.
%Y A371517 Cf. A349331, A371483, A371518.
%Y A371517 Cf. A371486.
%K A371517 nonn
%O A371517 0,2
%A A371517 _Seiichi Manyama_, Mar 26 2024