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 A364339 #14 Mar 24 2025 22:34:04
%S A364339 1,2,13,150,1978,28603,438273,6992052,114915180,1932233883,
%T A364339 33081722359,574755965137,10107627041697,179576579730534,
%U A364339 3218352405778284,58114340679967608,1056284029850962674,19310039426151335622,354818596435147647654,6549556302551204621664,121394125733645986376838
%N A364339 G.f. satisfies A(x) = (1 + x) * (1 + x*A(x)^6).
%F A364339 a(n) = Sum_{k=0..n} binomial(6*k+1,k) * binomial(6*k+1,n-k) / (6*k+1).
%t A364339 terms = 21; A[_] = 0; Do[A[x_] = (1+x)(1+x*A[x]^6) + O[x]^terms // Normal, terms]; CoefficientList[A[x], x] (* _Stefano Spezia_, Mar 24 2025 *)
%o A364339 (PARI) a(n) = sum(k=0, n, binomial(6*k+1, k)*binomial(6*k+1, n-k)/(6*k+1));
%Y A364339 Cf. A073157, A364336, A364337, A364338.
%Y A364339 Cf. A239109, A364333, A364340.
%K A364339 nonn
%O A364339 0,2
%A A364339 _Seiichi Manyama_, Jul 19 2023