A369446 Denominator of sigma(n) / A276086(n), where A276086 is the primorial base exp-function.

2, 1, 3, 9, 3, 5, 5, 1, 30, 5, 15, 25, 25, 25, 25, 225, 25, 125, 25, 125, 375, 125, 375, 125, 1250, 625, 375, 5625, 375, 7, 7, 1, 7, 7, 21, 5, 35, 7, 15, 7, 15, 175, 175, 25, 175, 175, 525, 875, 1750, 875, 875, 1125, 875, 875, 4375, 875, 2625, 875, 2625, 7, 49, 49, 147, 441, 21, 245, 245, 35, 245, 245, 245, 245, 1225

Offset: 1

Author

Antti Karttunen, Jan 25 2024

Keywords

• nonn
• frac

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Index entries for sequences related to primorial base
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A276086, A324644, A369445 (numerators).

Programs

PARI

A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A369446(n) = { my(u=A276086(n)); (u/gcd(u,sigma(n))); };

Formula

a(n) = A276086(n) / A324644(n).