OFFSET
1,2
EXAMPLE
We have 90 = prime(1) * prime(2)^2 * prime(3), so a(90) = prime(1) * prime(1)^2 * prime(2) = 24.
MATHEMATICA
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
mtf[f_][n_]:=Product[If[f[i]==0, 1, Prime[f[i]]], {i, primeMS[n]}];
Array[mtf[PartitionsQ], 100]
PROG
(PARI) f9(n) = polcoeff( prod( k=1, n, 1 + x^k, 1 + x * O(x^n)), n); \\ A000009
a(n) = my(f=factor(n)); for (k=1, #f~, f[k, 1] = prime(f9(primepi(f[k, 1])))); factorback(f); \\ Michel Marcus, Oct 25 2022
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Gus Wiseman, Oct 24 2022
STATUS
approved