A371914 G.f. A(x) satisfies A(x) = 1 - x/A(x)^3 * (1 - A(x) - A(x)^5).

1, 1, 3, 7, 15, 43, 168, 626, 2005, 6245, 22266, 87365, 328727, 1154975, 4086410, 15464587, 60368094, 229327457, 847539610, 3174058754, 12277874065, 47912709420, 184171945435, 701491726600, 2700878181660, 10556457650417, 41330116314628

Offset

0,3

Links

Table of n, a(n) for n=0..26.

Formula

a(n) = (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(2*n-5*k,n-k-1) for n > 0.

Prog

(PARI) a(n) = if(n==0, 1, sum(k=0, n, binomial(n, k)*binomial(2*n-5*k, n-k-1))/n);

Crossrefs

Cf. A349332, A367725, A371913, A371915.

Sequence in context: A147188 A050565 A097111 * A151401 A080567 A276969

Adjacent sequences: A371911 A371912 A371913 * A371915 A371916 A371917

Keyword

nonn

Author

Seiichi Manyama, Apr 12 2024

Status

approved