A365736 - OEIS

%I #12 Sep 17 2023 10:05:08

%S 1,1,1,1,1,1,2,7,22,57,127,254,478,903,1838,4148,10012,24417,58019,

%T 132919,295699,649742,1437719,3247500,7504925,17607055,41465646,

%U 97197400,226053017,522505492,1205674911,2790322418,6495170018,15209566913,35761582618

%N G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^5*A(x)^4).

%F a(n) = Sum_{k=0..floor(n/5)} binomial(n-4*k-1,k) * binomial(n-k+1,n-5*k) / (n-k+1).

%o (PARI) a(n) = sum(k=0, n\5, binomial(n-4*k-1, k)*binomial(n-k+1, n-5*k)/(n-k+1));

%Y Cf. A212364, A212385, A365734, A365735.

%Y Cf. A365701.

%K nonn

%O 0,7

%A _Seiichi Manyama_, Sep 17 2023