OFFSET
1,2
EXAMPLE
a(12) = a(2^2 * 3^1) = prime(2)^prime(2) + prime(3)^prime(1) = 3^3 + 5^2 = 52.
MATHEMATICA
a[n_] := Plus @@ (Prime[#[[1]]]^Prime[#[[2]]] & /@ FactorInteger[n]); a[1] = 0; Table[a[n], {n, 50}]
PROG
(PARI) a(n) = my(f=factor(n)); for (k=1, #f~, f[k, 1] = prime(f[k, 1])^prime(f[k, 2]); ); vecsum(f[, 1]); \\ Michel Marcus, Nov 30 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 30 2018
STATUS
approved