OFFSET
1,2
COMMENTS
All terms are in A048103.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..20000
FORMULA
Multiplicative with a(p^e) = p^(p-1) if e >= p, otherwise a(p^e) = p^e.
Sum_{k=1..n} a(k) ~ c * n^2, where c = (1/2) * Product_{p prime} (1 - 1/((p+1)*p^(p-1))) = 0.40498413761092854213... . - Amiram Eldar, Nov 07 2022
MATHEMATICA
f[p_, e_] := If[e >= p, p^(p - 1), p^e]; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Nov 07 2022 *)
PROG
(PARI) A327937(n) = { my(f = factor(n)); for(k=1, #f~, if(f[k, 2]>=f[k, 1], f[k, 2] = f[k, 1]-1)); factorback(f); };
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Antti Karttunen, Oct 01 2019
STATUS
approved