A186183 Expansion of 1/(1-x*A002295(x)).

1, 1, 2, 9, 68, 646, 6857, 77695, 919642, 11233858, 140544189, 1791614714, 23187320736, 303861373679, 4023883823059, 53762917329659, 723854999871943, 9811154512175468, 133762940465746744, 1833187046654598058, 25239961633188882896

Offset

0,3

Links

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

Vladimir Kruchinin and D. V. Kruchinin, Composita and their properties, arXiv:1103.2582 [math.CO], 2011-2013.

Formula

a(n) = Sum_{k=1..n} k/(5*n-4*k) * binomial(6*n-5*k-1,n-k) if n>0; a(0)=1.

Maple

a:= n-> `if` (n=0, 1, add (k/(5*n-4*k) *binomial (6*n-5*k-1, n-k), k=1..n)):
seq (a(n), n=0..30);

Prog

(PARI) a(n)=max(1, sum(k=1, n, k/(5*n-4*k)*binomial(6*n-5*k-1, n-k)))

Crossrefs

Sequence in context: A336588 A322612 A364337 * A295239 A120020 A200248

Adjacent sequences: A186180 A186181 A186182 * A186184 A186185 A186186

Keyword

nonn

Author

_Vladimir Kruchinin_, Feb 14 2011

Status

approved