A186182 Expansion of 1/(1-x*A002294(x)).

1, 1, 2, 8, 50, 388, 3363, 31132, 301156, 3007000, 30753169, 320492869, 3391067666, 36331532588, 393353506931, 4296895624750, 47300050998991, 524168531729460, 5842914510975105, 65470405191871331, 737008925038212059, 8331166456981245521

Offset

0,3

Links

Table of n, a(n) for n=0..21.

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/(4*n-3*k)*binomial(5*n-4*k-1,n-k), n>0; a(0) = 1.

Mathematica

Join[{1}, Table[Sum[k/(4n-3k) Binomial[5n-4k-1, n-k], {k, n}], {n, 30}]] (* Harvey P. Dale, Feb 05 2012 *)

Prog

(PARI) a(n)=max(1, sum(k=1, n, k/(4*n-3*k)*binomial(5*n-4*k-1, n-k)))

Crossrefs

Cf. A002294.

Sequence in context: A034491 A360949 A231352 * A274273 A121677 A120956

Adjacent sequences: A186179 A186180 A186181 * A186183 A186184 A186185

Keyword

nonn

Author

Vladimir Kruchinin, Feb 14 2011

Status

approved