A319821 a(n) = log_2(A094269(n)).

0, 0, 1, 1, 2, 1, 2, 2, 2, 3, 3, 4, 3, 3, 3, 4, 4, 4, 4, 5, 4, 5, 5, 5, 6, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 8, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 8, 8, 8, 9, 9, 9, 9, 10, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 10, 11, 11, 11, 12

Offset

1,5

Comments

A companion sequence of A094269.

Links

Table of n, a(n) for n=1..82.

Formula

phi(A003401(n)) = A094269(n) = 2^a(n).

Prog

(PARI) for(n=1, 1e4, my(i=eulerphi(n)); if(omega(2*i)==1, print1(logint(i, 2), ", ")))

Crossrefs

A000010, A003401, A094269.

Sequence in context: A280128 A354703 A070096 * A024154 A117875 A084840

Adjacent sequences: A319818 A319819 A319820 * A319822 A319823 A319824

Keyword

nonn

Author

Jianing Song, Sep 28 2018

Status

approved