A392878 a(n) = A276086(A276085(n)), where A276085 and A276086 are primorial base log and exp-functions.

1, 2, 3, 3, 5, 6, 7, 6, 9, 10, 11, 9, 13, 14, 15, 9, 17, 18, 19, 15, 21, 22, 23, 18, 25, 26, 5, 21, 29, 30, 31, 18, 33, 34, 35, 5, 37, 38, 39, 30, 41, 42, 43, 33, 45, 46, 47, 5, 49, 50, 51, 39, 53, 10, 55, 42, 57, 58, 59, 45, 61, 62, 63, 5, 65, 66, 67, 51, 69, 70, 71, 10, 73, 74, 75, 57, 77, 78, 79, 45, 15, 82, 83

Offset

1,2

Comments

These are the stable (fixed) points eventually reached when iterating A392879 starting from n.

This sequence contains only terms of A048103.

Links

Antti Karttunen, Table of n, a(n) for n = 1..12000

Index entries for sequences related to primorial base.

Formula

a(n) = n - A376418(n).

Prog

(PARI)
A276085(n) = { my(f=factor(n)); sum(k=1, #f~, f[k, 2]*prod(i=1, primepi(f[k, 1]-1), prime(i))); };
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A392878(n) = A276086(A276085(n));

Crossrefs

Cf. A048103 (fixed points), A276085, A276086, A376418, A392879.

Differs from analogous A392877 first at n=625, where a(625) = 625.

Cf. also A097248 for analogous sequence in base-2.

Sequence in context: A063659 A384249 A392877 * A392879 A255563 A331288

Adjacent sequences: A392875 A392876 A392877 * A392879 A392880 A392881

Keyword

nonn,easy

Author

Antti Karttunen, Jan 31 2026

Status

approved