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 A364340 #12 Jul 19 2023 07:48:38
%S A364340 1,2,15,179,2502,38262,619991,10459410,181771289,3231782239,
%T A364340 58505593456,1074766446526,19984671314164,375414901633692,
%U A364340 7113886504446443,135820770971898805,2610186429457347486,50452256583633573513,980187901557594671335,19130197594133100828170,374894511736219913097375
%N A364340 G.f. satisfies A(x) = (1 + x*A(x)) * (1 + x*A(x)^6).
%F A364340 a(n) = Sum_{k=0..n} binomial(n+5*k+1,k) * binomial(n+5*k+1,n-k) / (n+5*k+1).
%o A364340 (PARI) a(n) = sum(k=0, n, binomial(n+5*k+1, k)*binomial(n+5*k+1, n-k)/(n+5*k+1));
%Y A364340 Cf. A239109, A364333, A364339.
%Y A364340 Cf. A007863, A198953, A215623, A215624.
%K A364340 nonn
%O A364340 0,2
%A A364340 _Seiichi Manyama_, Jul 19 2023