OFFSET
0,3
COMMENTS
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
FORMULA
Fully multiplicative with a(prime(n)) = A056239(n), restricted to odd n.
EXAMPLE
91 has prime indices {4,6} with prime indices {{1,1},{1,2}} with sums {2,3} with product a(45) = 6.
MATHEMATICA
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Table[Times@@Plus@@@primeMS/@primeMS[n], {n, 1, 200, 2}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 25 2019
STATUS
approved