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 A070633 a(n) is the number of k>0 such that phi(k) divides n. 4
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Inverse MÃ¶bius transform of A014197. - Antti Karttunen, Sep 10 2018 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA From Antti Karttunen, Sep 10 2018: (Start) a(n) = Sum_{d|n} A014197(d). a(n) >= A069932(n). a(A000010(n)) = A071181(n). (End) PROG (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 A070633(n) = sumdiv(n, d, A014197(d)); \\ Antti Karttunen, Sep 10 2018 CROSSREFS Cf. A000010, A014197, A069932, A071181, A319048. Sequence in context: A134349 A131711 A131201 * A266256 A247551 A273580 Adjacent sequences:  A070630 A070631 A070632 * A070634 A070635 A070636 KEYWORD easy,nonn AUTHOR Benoit Cloitre, May 13 2002 STATUS approved

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Last modified May 31 06:22 EDT 2020. Contains 334747 sequences. (Running on oeis4.)