A360893 G.f. satisfies A(x) = 1 + x/(1 - x^4)^2 * A(x/(1 - x^4)).

1, 1, 1, 1, 1, 3, 6, 10, 15, 24, 51, 109, 214, 389, 747, 1595, 3497, 7379, 15065, 31750, 70504, 159352, 353748, 777240, 1742696, 4022595, 9379659, 21717264, 50239529, 117913537, 281584044, 676667552, 1623733085, 3908144320, 9509212539, 23393422297, 57815808829

Offset

0,6

Links

Table of n, a(n) for n=0..36.

Formula

a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/4)} binomial(n-3*k,k) * a(n-1-4*k).

Prog

(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\4, binomial(i-3*j, j)*v[i-4*j])); v;

Crossrefs

Cf. A040027, A352864, A360892.

Cf. A360891, A360901.

Sequence in context: A026104 A261632 A058576 * A365696 A346734 A366132

Adjacent sequences: A360890 A360891 A360892 * A360894 A360895 A360896

Keyword

nonn

Author

Seiichi Manyama, Feb 25 2023

Status

approved