login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

G.f. satisfies A(x) = 1 + x / (1 + x*A(x))^3.
4

%I #9 Aug 22 2023 07:57:21

%S 1,1,-3,3,11,-54,66,297,-1575,1980,10300,-55392,68352,403583,-2153685,

%T 2551845,16999045,-89142087,99986901,750955382,-3850437018,4041467331,

%U 34310059311,-171533033904,166630375248,1607168518073,-7821913867611,6950050797297

%N G.f. satisfies A(x) = 1 + x / (1 + x*A(x))^3.

%F If g.f. satisfies A(x) = 1 + x/(1 + x*A(x))^s, then a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n-k+1,k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).

%o (PARI) a(n, s=3) = sum(k=0, n, (-1)^(n-k)*binomial(n-k+1, k)*binomial(n+(s-1)*k-1, n-k)/(n-k+1));

%Y Cf. A007440, A365109, A365111, A365112.

%Y Cf. A365086.

%K sign

%O 0,3

%A _Seiichi Manyama_, Aug 22 2023