OFFSET
1,2
FORMULA
MATHEMATICA
f[p_, e_] := If[e == 1, 3*p - 1, (3*e*(p - 1) + 3)*p^(e - 1)]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Jan 19 2023 *)
PROG
(PARI) a(n) = my(f=factor(n), p, e); for (k=1, #f~, p=f[k, 1]; e=f[k, 2]; f[k, 1] = if (e == 1, 3*p-1, (3*e*(p-1) + 3) * p^(e-1)); f[k, 2] = 1); factorback(f); \\ Michel Marcus, Jan 21 2023
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Werner Schulte, Jan 19 2023
STATUS
approved