A366183 G.f. A(x) satisfies A(x) = 1/(1 - x)^3 + x*A(x)^3/(1 - x)^2.

1, 4, 20, 145, 1250, 11746, 116641, 1204039, 12790067, 138895021, 1535005454, 17207743738, 195197256289, 2236419124408, 25842382083071, 300822398531482, 3524358836945936, 41524956284752018, 491722951928324392, 5848997420625891294, 69854562522309219081

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

a(n) = Sum_{k=0..n} binomial(n+7*k+2,n-k) * binomial(3*k,k)/(2*k+1).

Prog

(PARI) a(n) = sum(k=0, n, binomial(n+7*k+2, n-k)*binomial(3*k, k)/(2*k+1));

Crossrefs

Cf. A364623, A366182, A366184.

Sequence in context: A034216 A144009 A301270 * A117887 A082988 A001171

Adjacent sequences: A366180 A366181 A366182 * A366184 A366185 A366186

Keyword

nonn

Author

Seiichi Manyama, Oct 03 2023

Status

approved