A014484 Expansion of (1+2x)/(1-2x)^4 (E.g.f.).

1, 10, 112, 1440, 21120, 349440, 6451200, 131604480, 2941747200, 71530905600, 1880240947200, 53137244160000, 1606870263398400, 51776930709504000, 1771128112545792000, 64103411041173504000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Robert Israel, Table of n, a(n) for n = 0..400

Crossrefs

Cf. A006157.

Programs

Maple

seq((n+1)*(n+2)*(2*n+3)/6 * 2^n * n!, n=0..30); # Robert Israel, Jul 11 2018

PARI

a(n)=(n+1)*(n+2)*(2*n+3)/6*2^n*n! \\ Charles R Greathouse IV, Jun 11 2013

Formula

a(n) = (n+1)(n+2)(2n+3)/6 * 2^n * n!. - Ralf Stephan, Mar 24 2004

Conjecture: a(n) +(-2*n-9)*a(n-1) +6*(n+1)*a(n-2)=0. - R. J. Mathar, Jun 11 2013

Conjecture verified by Robert Israel, Jul 11 2018