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

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Last modified December 8 09:32 EST 2019. Contains 329862 sequences. (Running on oeis4.)