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A070804 Number of primes not exceeding phi[n]. 9
0, 0, 1, 1, 2, 1, 3, 2, 3, 2, 4, 2, 5, 3, 4, 4, 6, 3, 7, 4, 5, 4, 8, 4, 8, 5, 7, 5, 9, 4, 10, 6, 8, 6, 9, 5, 11, 7, 9, 6, 12, 5, 13, 8, 9, 8, 14, 6, 13, 8, 11, 9, 15, 7, 12, 9, 11, 9, 16, 6, 17, 10, 11, 11, 15, 8, 18, 11, 14, 9, 19, 9, 20, 11, 12, 11, 17, 9, 21, 11, 16, 12, 22, 9, 18, 13, 16 (list; graph; refs; listen; history; internal format)
OFFSET

1,5

FORMULA

a(n)=A000720[A000010(n)]=Pi[phi[n]]

EXAMPLE

n=50: phi[50]=20,Pi[20]=8=a(50)

MATHEMATICA

Table[PrimePi[EulerPhi[n]], {n, 1, 256}]

CROSSREFS

Cf. A007818, A000010, A000720, A070800-A070804.

Sequence in context: A110917 A070956 A007828 * A104481 A078709 A023022

Adjacent sequences:  A070801 A070802 A070803 * A070805 A070806 A070807

KEYWORD

easy,nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), May 08 2002

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Last modified February 15 17:13 EST 2012. Contains 205828 sequences.