A279690 Smallest number with equivalent prime tower factorization as n.

1, 2, 2, 4, 2, 6, 2, 8, 8, 6, 2, 12, 2, 6, 6, 16, 2, 18, 2, 12, 6, 6, 2, 18, 8, 6, 4, 12, 2, 30, 2, 8, 6, 6, 6, 36, 2, 6, 6, 40, 2, 30, 2, 12, 40, 6, 2, 48, 8, 18, 6, 12, 2, 12, 6, 40, 6, 6, 2, 60, 2, 6, 40, 64, 6, 30, 2, 12, 6, 30, 2, 72, 2, 6, 40, 12, 6, 30

Offset

1,2

Comments

A279686 defines the prime tower factorization equivalence classes.

This sequence is to A279686 what A046523 is to A025487.

a(a(n))=a(n) for any n>0.

a(n)=n iff n belongs to A279686.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Prime tower factorization of the first terms

Rémy Sigrist, PARI program for A279690

Crossrefs

Cf. A279686, A025487, A046523.

Sequence in context: A307088 A143112 A286472 * A167272 A090624 A304407

Adjacent sequences: A279687 A279688 A279689 * A279691 A279692 A279693

Keyword

nonn

Author

Rémy Sigrist, Dec 17 2016

Status

approved