OFFSET
1,1
COMMENTS
Sum[ i^n, {i,1,k} ] = Zeta[ -n ] - Zeta[ -n, k+1 ]. Product[ i^n, {i,1,k} ] = (k!)^n.
a(11) > 1091730. - Robert G. Wilson v, Jan 25 2007
MATHEMATICA
f[n_] := Block[{k = 2, p = s = 1}, While[p = p*k; s = s + k^n; PowerMod[p, n, s] != 0, k++ ]; k]; (* Robert G. Wilson v *)
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Jan 18 2007
EXTENSIONS
a(8)-a(10) from Robert G. Wilson v, Jan 25 2007
STATUS
approved