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 A379174 #8 Dec 17 2024 10:12:18
%S A379174 1,3,20,176,1772,19309,221651,2640016,32322122,404256442,5142846467,
%T A379174 66341063274,865723122919,11408144684248,151593390664710,
%U A379174 2029025599194394,27330120599494110,370183683091079836,5038997387800717228,68896081533831380702,945747379824209853435
%N A379174 G.f. A(x) satisfies A(x) = (1 + x*A(x)^3)/(1 - x*A(x))^2.
%F A379174 a(n) = Sum_{k=0..n} binomial(n+2*k+1,k) * binomial(3*n+3*k+1,n-k)/(n+2*k+1).
%o A379174 (PARI) a(n) = sum(k=0, n, binomial(n+2*k+1, k)*binomial(3*n+3*k+1, n-k)/(n+2*k+1));
%Y A379174 Cf. A003169, A249924, A379173.
%K A379174 nonn
%O A379174 0,2
%A A379174 _Seiichi Manyama_, Dec 17 2024