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A319821
a(n) = log_2(A094269(n)).
2
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
FORMULA
2^a(n) = A094269(n) = phi(A003401(n)).
PROG
(PARI) for(n=1, 1e4, my(i=eulerphi(n)); if(omega(2*i)==1, print1(logint(i, 2), ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Jianing Song, Sep 28 2018
STATUS
approved