A331286 Odd part of number of divisors of primorial inflation of n: a(n) = A000265(A329605(n)).

1, 1, 1, 3, 1, 3, 1, 1, 9, 3, 1, 1, 1, 3, 9, 5, 1, 3, 1, 1, 9, 3, 1, 5, 27, 3, 1, 1, 1, 3, 1, 3, 9, 3, 27, 15, 1, 3, 9, 5, 1, 3, 1, 1, 1, 3, 1, 3, 81, 9, 9, 1, 1, 5, 27, 5, 9, 3, 1, 15, 1, 3, 1, 7, 27, 3, 1, 1, 9, 9, 1, 9, 1, 3, 3, 1, 81, 3, 1, 3, 25, 3, 1, 15, 27, 3, 9, 5, 1, 5, 81, 1, 9, 3, 27, 7, 1, 27, 1, 45, 1, 3, 1, 5, 3

Offset: 1

Author

Antti Karttunen, Jan 14 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Crossrefs

Cf. A000265, A108951, A212181, A329605.

Cf. also A322865.

Programs

PARI

A331286(n) = if(1==n,1,my(f=factor(n),e=1,m=1); forstep(i=#f~,1,-1, e += f[i,2]; m *= (e>>valuation(e,2))^(primepi(f[i,1])-if(1==i,0,primepi(f[i-1,1])))); (m));

Formula

a(n) = A000265(A329605(n)).

a(n) = A212181(A108951(n)).