OFFSET
1,2
COMMENTS
Prime p divides a(2p-1). Prime p divides a(3p-1), p>2. Prime p divides a(p-1), p>2. p^2 divides a(p^2-1) for prime p>2. p^3 divides a(p^3-1) for prime p>2. p^4 divides a(p^4-1) for prime p>2. p^5 divides a(p^5-1) for prime p>2.
FORMULA
a(n) = numerator[ Sum[i^3/(n-i+1)^2, {i,1,n}]].
MATHEMATICA
Numerator[Table[Sum[i^3/(n-i+1)^2, {i, 1, n}], {n, 1, 50}]]
CROSSREFS
KEYWORD
frac,nonn
AUTHOR
Alexander Adamchuk, Jun 25 2006
STATUS
approved