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 A367030 #8 Nov 02 2023 10:40:24
%S A367030 1,1,0,-5,-15,0,170,619,69,-8351,-33601,-8446,480679,2078534,830739,
%T A367030 -30221481,-138791261,-76306831,2009474129,9742939809,6811893809,
%U A367030 -138835809721,-708398431831,-599833654686,9861055840019,52859680413599,52446605719469
%N A367030 G.f. satisfies A(x) = 1 + x*A(x) - x^2*A(x)^5.
%F A367030 a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(n+3*k,k) * binomial(n+2*k,n-2*k) / (4*k+1).
%o A367030 (PARI) a(n) = sum(k=0, n\2, (-1)^k*binomial(n+3*k, k)*binomial(n+2*k, n-2*k)/(4*k+1));
%Y A367030 Cf. A343773, A367028, A367029.
%Y A367030 Cf. A182454.
%K A367030 sign
%O A367030 0,4
%A A367030 _Seiichi Manyama_, Nov 02 2023