A110416 a(n) = Sum_{k<n, k!==0 (mod n)} k!/n.

1, 0, 0, 0, 0, 25, 0, 738, 5120, 40908, 0, 3662892, 0, 482141160, 6261884552, 87600164760, 0, 21000656701120, 0, 6421274296759014, 121967975910086640, 2438739530264419200, 0, 1126236239013683565846, 25899122858782713781248

Offset

1,6

Comments

a(n)=0 if and only if n is a prime or n=4. - Emeric Deutsch, Aug 05 2005

Links

Table of n, a(n) for n=1..25.

Example

a(9) = (6! + 7! + 8!)/9 = 5120.

Maple

a:=proc(n) local A, k: A:={}: for k from 0 to n-1 do if k! mod n = 0 then A:=A union {k} else A:=A: fi od: sum(A[j]!, j=1..nops(A))/n end: seq(a(n), n=1..27); # Emeric Deutsch, Aug 05 2005

Crossrefs

Sequence in context: A108321 A059062 A179809 * A028848 A172298 A040630

Adjacent sequences: A110413 A110414 A110415 * A110417 A110418 A110419

Keyword

easy,nonn

Author

Amarnath Murthy, Aug 01 2005

Extensions

More terms from Emeric Deutsch, Aug 05 2005

Status

approved