OFFSET
1,2
EXAMPLE
a(1) = 0 since 1! = 1 has no prime factor;
a(8) = 2^7 + 3^2 + 5 + 7 = 149 since 8! = 2^7*3^2*5*7.
MATHEMATICA
ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] ep[x_] := Table[Part[ffi[x], 2*w], {w, 1, lf[x]}] supo[x_] := Apply[Plus, ba[x]^ep[x]] Table[supo[w], {w, 1, 25}]
PROG
(PARI) a(n) = my(f=factor(n!)); sum(k=1, #f~, f[k, 1]^f[k, 2]); \\ Michel Marcus, Jul 09 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Mar 31 2003
STATUS
approved