login
a(n) = meantorial(n) = the product of the set of n closest numbers with an arithmetic mean of n.
1

%I #4 Dec 05 2013 19:57:01

%S 1,3,24,180,2520,30240,604800,9979200,259459200,5448643200,

%T 174356582400,4446092851200,168951528345600,5068545850368000,

%U 223016017416192000,7694052600858624000,384702630042931200000,15003402571674316800000

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

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

%F 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).

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

%Y Cf. A110348.

%K easy,nonn

%O 1,2

%A _Amarnath Murthy_, Jul 21 2005

%E More terms from _Joshua Zucker_, May 08 2006