OFFSET
1,2
COMMENTS
p^3 divides a(p^k) for prime p>2 and integer k>0.
FORMULA
MATHEMATICA
Numerator[Table[Sum[Sum[1/(i+j-1), {i, 1, n}], {j, 1, n}], {n, 1, 25}]] - Denominator[Table[Sum[Sum[1/(i+j-1), {i, 1, n}], {j, 1, n}], {n, 1, 25}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Jul 22 2006
STATUS
approved