A114253 a(n) = C(5+2*n,5+n)*C(10+2*n,0+n).

1, 84, 3276, 92400, 2187900, 46558512, 923410488, 17439488352, 317907339750, 5644249611000, 98209943231400, 1682207622669600, 28457345616827400

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..828

Formula

From Robert Israel, Jan 11 2019: (Start)

(n+1)^2*(11+n)*a(n+1)=4*(7+2*n)*(3+n)*(11+2*n)*a(n).

a(n) ~ 32768*16^n/(Pi*n). (End)

Example

If n=1 then C(5+2*1,5+1)*C(10+2*1,0+1) = C(7,6)*C(12,1) = 7*12 = 84.
If n=11 then C(5+2*n,5+n)*C(10+2*n,0+n) = C(27,16)*C(32,11) = 13037895*129024480 = 1682207622669600.

Maple

seq(binomial(5+2*n, 5+n)*binomial(10+2*n, n), n=0..30); # Robert Israel, Jan 11 2019

Crossrefs

Cf. A062190.

Sequence in context: A219470 A219372 A026809 * A017800 A035737 A035806

Adjacent sequences: A114250 A114251 A114252 * A114254 A114255 A114256

Keyword

easy,nonn

Author

Zerinvary Lajos, Feb 04 2006

Status

approved