A110347 a(n) = meantorial(n) = the product of the set of n closest numbers with an arithmetic mean of n.

1, 3, 24, 180, 2520, 30240, 604800, 9979200, 259459200, 5448643200, 174356582400, 4446092851200, 168951528345600, 5068545850368000, 223016017416192000, 7694052600858624000, 384702630042931200000, 15003402571674316800000

Offset

1,2

Comments

a(n) ==0 (mod n), except for n=2.

Links

Table of n, a(n) for n=1..18.

Formula

a(2n+1) = (n+1)(n+2)...(2n+1)(2n+2) ...(3n+1)(3n+2). a(2n) = n(n+1)(n+2)...(2n-2)(2n-1)(2n+1)(2n+2)...(3n-1)(3n).

Example

a(3) = 2*3*4 = 24, a(6)= 3*4*5*7*8*9 = 30240.

Crossrefs

Cf. A110348.

Sequence in context: A317527 A181967 A144087 * A213100 A027324 A122741

Adjacent sequences: A110344 A110345 A110346 * A110348 A110349 A110350

Keyword

easy,nonn

Author

Amarnath Murthy, Jul 21 2005

Extensions

More terms from Joshua Zucker, May 08 2006

Status

approved