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A070633
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a(n) is the number of k>0 such that phi(k) divides n.
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4
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2, 5, 2, 9, 2, 9, 2, 14, 2, 7, 2, 19, 2, 5, 2, 20, 2, 13, 2, 16, 2, 7, 2, 34, 2, 5, 2, 11, 2, 13, 2, 27, 2, 5, 2, 31, 2, 5, 2, 30, 2, 13, 2, 14, 2, 7, 2, 51, 2, 7, 2, 11, 2, 15, 2, 19, 2, 7, 2, 37, 2, 5, 2, 35, 2, 13, 2, 9, 2, 9, 2, 63, 2, 5, 2, 9, 2, 11, 2, 46, 2, 7, 2, 31, 2, 5, 2, 25, 2, 17, 2
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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(End)
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PROG
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(PARI) for(n=1, 120, print1(sum(i=1, 100*n, if(n%eulerphi(i), 0, 1)), ", "));
(PARI)
\\ In contrast to above program, this is safe in any range 1..n:
A014197(n, m=1) = { n==1 && return(1+(m<2)); my(p, q); sumdiv(n, d, if( d>=m && isprime(d+1), sum( i=0, valuation(q=n\d, p=d+1), A014197(q\p^i, p))))}; \\ From A014197 by M. F. Hasler
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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