OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..10000
MATHEMATICA
b[n_] := Product[{p, e} = pe; (PrimePi[p] + 1)^e, {pe, FactorInteger[n]}];
a[n_] := b[b[n]];
Array[a, 100] (* Jean-François Alcover, Nov 21 2021 *)
PROG
(PARI) \\ here b(n) is A064553.
b(n)={my(f=factor(n)); prod(i=1, #f~, (primepi(f[i, 1])+1)^f[i, 2])}
a(n)={b(b(n))} \\ Andrew Howroyd, Nov 18 2025
CROSSREFS
KEYWORD
mult,nonn
AUTHOR
Reinhard Zumkeller, Sep 21 2001
STATUS
approved