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A001836 Numbers n such that phi(2n-1) < phi(2n), where phi is Euler's totient function A000010.
(Formerly M5429 N2359)
+0
1
53, 83, 158, 263, 293, 368, 578, 683, 743, 788, 878, 893, 908, 998, 1073, 1103, 1208, 1238, 1268, 1403, 1418, 1502, 1523, 1658, 1733, 1838, 1943, 1964, 2048, 2063, 2153, 2228, 2243, 2258, 2363, 2393, 2423, 2468, 2558, 2573, 2633, 2657, 2678 (list; graph; listen)
OFFSET

1,1

REFERENCES

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

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

V. L. Klee, Jr., Some remarks on Euler's totient function, Amer. Math. Monthly, 54 (1947), 332.

J. O. Shallit, personal communication.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

Don Reble, Python program

CROSSREFS

Cf. A000010.

Sequence in context: A059245 A125876 A136065 this_sequence A144939 A118149 A119289

Adjacent sequences: A001833 A001834 A001835 this_sequence A001837 A001838 A001839

KEYWORD

nonn,nice

AUTHOR

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

EXTENSIONS

Corrected and extended by Don Reble (djr(AT)nk.ca), Jan 04 2007

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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