A384974 G.f. A(x) satisfies A(x) = 1 + x*A(x)/A(-x*A(x)^3)^2.

1, 1, 3, 8, 25, 57, 22, -1003, -9967, -67627, -394013, -1958808, -7869346, -17261270, 104411359, 1931214493, 19188604691, 153913872501, 1080677292567, 6709916699425, 35489004465351, 135918792966633, -9832967202556, -7535958768199373, -106301159541342282

Offset

0,3

Links

Table of n, a(n) for n=0..24.

Formula

See A384977.

Prog

(PARI) a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-3*n+3*j+k-1, j-1)*a(n-j, 2*j)/j));

Crossrefs

Column k=1 of A384977.

Sequence in context: A057420 A394241 A076049 * A026970 A026980 A026955

Adjacent sequences: A384971 A384972 A384973 * A384975 A384976 A384977

Keyword

sign

Author

Seiichi Manyama, Jun 14 2025

Status

approved