A264153 a(n) = ((2*n)!)^2 / 2^n.

1, 2, 144, 64800, 101606400, 411505920000, 3585039575040000, 59375425441812480000, 1710012252724199424000000, 80059353648041568632832000000, 5780285333388601255290470400000000, 616883611349898303167109582028800000000, 93983451956379706284115479041251737600000000

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Formula

a(n) = A134372(n)/A000079(n).

a(n)*A264152(n) = A134372(n)*A006882(2*n-1)/A006882(n).

a(n)/A264152(n) is integer 1, 1, 24, 1620,....

Maple

a := n -> (2*n)!^2/2^n; seq(a(n), n=0..10);

Prog

(Sage)
a = lambda n: factorial(2*n)^2 >> n
[a(n) for n in range(11)]

Crossrefs

Cf. A000079, A000680, A134372, A264152.

Sequence in context: A163275 A157073 A304461 * A232998 A103207 A093002

Adjacent sequences: A264150 A264151 A264152 * A264154 A264155 A264156

Keyword

nonn

Author

Peter Luschny, Nov 06 2015

Status

approved