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A002202 Values taken by totient function phi(m) (A000010).
(Formerly M0987 N0371)
+0
42
1, 2, 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 28, 30, 32, 36, 40, 42, 44, 46, 48, 52, 54, 56, 58, 60, 64, 66, 70, 72, 78, 80, 82, 84, 88, 92, 96, 100, 102, 104, 106, 108, 110, 112, 116, 120, 126, 128, 130, 132, 136, 138, 140, 144, 148, 150, 156, 160, 162, 164, 166, 168, 172, 176 (list; graph; listen)
OFFSET

1,2

COMMENT

These are the numbers n such that for some m the multiplicate group mod m has order n.

REFERENCES

J. W. L. Glaisher, Number-Divisor Tables. British Assoc. Math. Tables, Vol. 8, Camb. Univ. Press, 1940, p. 64.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

K. Ford, The distribution of totients, Electron. Res. Announc. Amer. Math. Soc. 4 (1998), 27-34.

Eric Weisstein's World of Mathematics, Totient Valence Function

MAPLE

with(numtheory); t1 := [seq(nops(invphi(n)), n=1..300)]; t2 := []: for n from 1 to 300 do if t1[n] <> 0 then t2 := [op(t2), n]; fi; od: t2;

CROSSREFS

Cf. A000010, A002180, A032446, A058277.

Sequence in context: A011860 A049445 A002174 this_sequence A049225 A076450 A097379

Adjacent sequences: A002199 A002200 A002201 this_sequence A002203 A002204 A002205

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified December 21 10:15 EST 2009. Contains 171081 sequences.


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