A111781 Eighth column (m=7) of unsigned triangle A111595.

1, 56, 2052, 63000, 1777050, 48149640, 1284709140, 34260506280, 921799753875, 25175488338000, 700755564108600, 19932553764723600, 580406741946731700, 17320767850295910000, 530112107596146075000, 16645556950225160958000

Offset

7,2

Links

Table of n, a(n) for n=7..22.

Formula

E.g.f. (1/sqrt(1-x^2))*((x/(1-x))^7)/7!.

a(n)=(n!/7!)*sum(binomial(2*k, k)*binomial(n-2*k-1, 6)/(4^k), k=0..floor((n-7)/2)), n>=7.

Crossrefs

Sequence in context: A332859 A004387 A111597 * A221398 A280803 A124101

Adjacent sequences: A111778 A111779 A111780 * A111782 A111783 A111784

Keyword

nonn,easy

Author

Wolfdieter Lang, Aug 23 2005

Status

approved