A379494 a(n) = 2*A276086(n) - A276086(A001065(n)), where A276086 is the primorial base exp-function, and A001065 is the sum of proper divisors of n.

3, 4, 10, 12, 34, 5, 18, 20, 51, 75, 178, -175, 98, 105, 270, 300, 898, -500, 498, -375, 1410, 2175, 4498, 1215, 2495, 3525, 7450, 5625, 22498, -161, 26, 28, -66, -249, 202, -8680, 138, -915, -30, -1995, 1258, -4025, 698, 735, 2058, 1275, 6298, -9275, 3485, 4900, 9750, 14175, 31498, 8505, 17050, 25809, 50250, 78729

Offset: 1

Author

Antti Karttunen, Jan 05 2025

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..30030
• Index entries for sequences related to primorial base.
• Index entries for sequences related to sigma(n).

Crossrefs

Cf. A001065, A276086, A379493.

Programs

PARI

A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A379494(n) = (2*A276086(n) - A276086(sigma(n)-n));

Formula

a(n) = 2*A276086(n) - A379493(n).