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A319695
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Number of distinct values obtained when Euler phi (A000010) is applied to proper divisors of n.
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6
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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
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1,6
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LINKS
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EXAMPLE
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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.
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PROG
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(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); };
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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