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A119434 Odd n such that 2*phi(n) < n. +0
4
105, 165, 195, 315, 495, 525, 585, 735, 825, 945, 975, 1155, 1365, 1485, 1575, 1755, 1785, 1815, 1995, 2145, 2205, 2415, 2475, 2535, 2625, 2805, 2835, 2925, 3003, 3045, 3135, 3255, 3315, 3465, 3675, 3705, 3795, 3885, 3927, 4095, 4125, 4305, 4389, 4455 (list; graph; listen)
OFFSET

1,1

COMMENT

Obviously 2*phi(n) = n is impossible for odd n. Odd elements of A054741 and A119432. This is not the same as A036798. 684411 = 3*7*13*23*109 is in this sequence but not in A036798. (This is may not be the smallest such value.) The primitive elements of this sequence are A119433, excluding the initial 2.

FORMULA

A036798 UNION A118700. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 08 2007

CROSSREFS

Cf. A000010, A054741, A119432.

Adjacent sequences: A119431 A119432 A119433 this_sequence A119435 A119436 A119437

Sequence in context: A118678 A076762 A036798 this_sequence A091495 A046405 A128278

KEYWORD

nonn

AUTHOR

Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 19 2006

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.


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