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 A379249 #5 Dec 19 2024 10:10:39
%S A379249 1,3,18,148,1403,14417,156161,1755664,20293341,239654554,2879027132,
%T A379249 35072400492,432238230583,5379422216020,67513288465855,
%U A379249 853481985400772,10858099927189575,138912471444569435,1786014309638224994,23065160118446902506,299062458173041384523
%N A379249 G.f. A(x) satisfies A(x) = (1 + x*A(x)^3) * (1 + x*A(x))^2.
%F A379249 a(n) = Sum_{k=0..n} binomial(n+2*k+1,k) * binomial(2*n+4*k+2,n-k)/(n+2*k+1).
%o A379249 (PARI) a(n) = sum(k=0, n, binomial(n+2*k+1, k)*binomial(2*n+4*k+2, n-k)/(n+2*k+1));
%Y A379249 Cf. A198953, A379190.
%K A379249 nonn
%O A379249 0,2
%A A379249 _Seiichi Manyama_, Dec 18 2024