OFFSET
0,2
LINKS
Robert Israel, Table of n, a(n) for n = 0..400
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
MAPLE
seq((n+1)*(n+2)*(2*n+3)/6 * 2^n * n!, n=0..30); # Robert Israel, Jul 11 2018
PROG
(PARI) a(n)=(n+1)*(n+2)*(2*n+3)/6*2^n*n! \\ Charles R Greathouse IV, Jun 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved