A053574 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A053574

Exponent of 2 in phi(n) where phi(n) = A000010(n).

0, 0, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 2, 1, 3, 3, 4, 1, 1, 3, 2, 1, 1, 3, 2, 2, 1, 2, 2, 3, 1, 4, 2, 4, 3, 2, 2, 1, 3, 4, 3, 2, 1, 2, 3, 1, 1, 4, 1, 2, 5, 3, 2, 1, 3, 3, 2, 2, 1, 4, 2, 1, 2, 5, 4, 2, 1, 5, 2, 3, 1, 3, 3, 2, 3, 2, 2, 3, 1, 5, 1, 3, 1, 3, 6, 1, 3, 3, 3, 3, 3, 2, 2, 1, 3, 5, 5, 1, 2, 3, 2, 5, 1, 4, 4, 2, 1, 2, 2, 3, 3, 4, 4, 2, 3, 3, 3, 1, 5, 5

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,5

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A007814(A000010(n)).

A000010(n) = A053575(n) * 2^a(n). - Antti Karttunen, May 26 2017

Additive with a(2^e) = e-1, and a(p^e) = A007814(p-1) for an odd prime p. - Amiram Eldar, Sep 05 2023

EXAMPLE

For n = 513 = 27*19, phi(513) = 4*81 so exponent of 2 is 2, thus a(513) = 2.

MATHEMATICA