OFFSET
1,2
LINKS
FORMULA
a(n) = n * A339905(n).
Sum_{k=1..n} a(k) ~ c * n^3, where c = (1/3) * Product_{p prime} ((p^2-p)/(p^2-q(p)+1)) = 0.49154782..., where q(p) = nextprime(p) = A151800(p). - Amiram Eldar, Dec 31 2022
MATHEMATICA
f[p_, e_] := ((NextPrime[p] - 1)*p)^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 60] (* Amiram Eldar, Dec 31 2022 *)
PROG
(PARI) A353793(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 1] = f[i, 1]*(nextprime(f[i, 1]+1)-1)); factorback(f); };
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Antti Karttunen, May 11 2022
STATUS
approved