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 A381940 #13 Mar 11 2025 07:57:06
%S A381940 1,2,7,51,440,4170,41921,438972,4736281,52286520,587774685,6705201456,
%T A381940 77426676892,903251324476,10629495065550,126032922655030,
%U A381940 1504194199010435,18056321542477095,217859030049153565,2640609137351540510,32137554969392230950,392580762083089376630
%N A381940 G.f. A(x) satisfies A(x) = (1 + x) * B(x*A(x)), where B(x) is the g.f. of A002293.
%F A381940 a(n) = Sum_{k=0..n} binomial(5*k+1,k) * binomial(k+1,n-k)/(5*k+1).
%F A381940 a(n) = A365184(n) + A365184(n-1).
%o A381940 (PARI) a(n) = sum(k=0, n, binomial(5*k+1, k)*binomial(k+1, n-k)/(5*k+1));
%Y A381940 Cf. A025227, A381787, A381937.
%Y A381940 Cf. A002293, A346647, A365184.
%K A381940 nonn
%O A381940 0,2
%A A381940 _Seiichi Manyama_, Mar 10 2025