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 A062821 Number of divisors of totient of n. 18
 1, 1, 2, 2, 3, 2, 4, 3, 4, 3, 4, 3, 6, 4, 4, 4, 5, 4, 6, 4, 6, 4, 4, 4, 6, 6, 6, 6, 6, 4, 8, 5, 6, 5, 8, 6, 9, 6, 8, 5, 8, 6, 8, 6, 8, 4, 4, 5, 8, 6, 6, 8, 6, 6, 8, 8, 9, 6, 4, 5, 12, 8, 9, 6, 10, 6, 8, 6, 6, 8, 8, 8, 12, 9, 8, 9, 12, 8, 8, 6, 8, 8, 4, 8, 7, 8, 8, 8, 8, 8, 12, 6, 12, 4, 12, 6, 12, 8, 12, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Harry J. Smith, Table of n, a(n) for n = 1..2000 FORMULA a(n) = A000005(A000010(n)). EXAMPLE The number of divisors of phi(n) can be greater than, less than, or equal to the number of divisors of n: .   n   phi(n)  d(phi(n))   d(n)   ==  ======  =========   ====   10     4        3     <   4   11    10        4     >   2   28    12        6     =   6 MATHEMATICA Array[DivisorSigma[0, EulerPhi[#]]&, 110] (* Harvey P. Dale, Jul 13 2012 *) PROG (PARI) { for (n=1, 2000, write("b062821.txt", n, " ", numdiv(eulerphi(n))) ) } \\ Harry J. Smith, Aug 11 2009 CROSSREFS Cf. A000005, A000010, A276044. Sequence in context: A323164 A318881 A280338 * A296080 A180633 A286610 Adjacent sequences:  A062818 A062819 A062820 * A062822 A062823 A062824 KEYWORD nonn AUTHOR Labos Elemer, Jul 20 2001 EXTENSIONS Offset corrected by Jaroslav Krizek, Jul 24 2009 Edited by Jon E. Schoenfield, Nov 13 2016 STATUS approved

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Last modified July 22 14:38 EDT 2019. Contains 325222 sequences. (Running on oeis4.)