OFFSET
1,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
f[p_, e_] := If[PrimeQ[PrimePi[p]], p^e, 1]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100]
PROG
(PARI) a(n) = {my(f = factor(n)); prod(i = 1, #f~, if(isprime(primepi(f[i, 1])), f[i, 1]^f[i, 2], 1)); }
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Amiram Eldar, Feb 03 2023
STATUS
approved