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 A371700 #10 Apr 03 2024 11:12:48
%S A371700 1,2,26,482,10450,247554,6208970,162064322,4356511138,119788611458,
%T A371700 3353361311738,95251219926690,2738421518770546,79531905952256642,
%U A371700 2329955712706784682,68770993359030211458,2043143866891345880898,61050342965542475675906
%N A371700 G.f. satisfies A(x) = 1 + x * A(x)^6 * (1 + A(x)).
%F A371700 a(n) = Sum_{k=0..n} binomial(n,k) * binomial(6*n+k+1,n)/(6*n+k+1).
%F A371700 a(n) = (1/n) * Sum_{k=0..n-1} (-1)^k * 2^(n-k) * binomial(n,k) * binomial(7*n-k,n-1-k) for n > 0.
%F A371700 a(n) = (1/n) * Sum_{k=1..n} 2^k * binomial(n,k) * binomial(6*n,k-1) for n > 0.
%o A371700 (PARI) a(n, r=1, t=6, u=1) = r*sum(k=0, n, binomial(n, k)*binomial(t*n+u*k+r, n)/(t*n+u*k+r));
%Y A371700 Cf. A006318, A027307, A144097, A260332, A363006.
%Y A371700 Cf. A371678.
%K A371700 nonn
%O A371700 0,2
%A A371700 _Seiichi Manyama_, Apr 03 2024