

A319695


Number of distinct values obtained when Euler phi (A000010) is applied to proper divisors of n.


6



0, 1, 1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 3, 3, 1, 3, 1, 3, 3, 2, 1, 3, 2, 2, 3, 3, 1, 4, 1, 4, 3, 2, 3, 4, 1, 2, 3, 4, 1, 4, 1, 3, 5, 2, 1, 4, 2, 3, 3, 3, 1, 4, 3, 5, 3, 2, 1, 4, 1, 2, 4, 5, 3, 4, 1, 3, 3, 4, 1, 6, 1, 2, 5, 3, 3, 4, 1, 5, 4, 2, 1, 5, 3, 2, 3, 5, 1, 6, 3, 3, 3, 2, 3, 5, 1, 3, 5, 5, 1, 4, 1, 5, 7
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OFFSET

1,6


LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537


EXAMPLE

For n = 6, it has three proper divisors: 1, 2, 3, and applying A000010 to these gives 1, 1 and 2, with just two distinct values, thus a(6) = 2.


PROG

(PARI) A319695(n) = { my(m=Map(), s, k=0); fordiv(n, d, if((d<n)&&!mapisdefined(m, s=eulerphi(d)), mapput(m, s, s); k++)); (k); };


CROSSREFS

Cf. A000010, A319696.
Cf. also A304793, A305611, A316555, A316556, A319685 for similarly constructed sequences.
Sequence in context: A105220 A083654 A164878 * A029428 A167866 A101422
Adjacent sequences: A319692 A319693 A319694 * A319696 A319697 A319698


KEYWORD

nonn


AUTHOR

Antti Karttunen, Oct 02 2018


STATUS

approved



