id:A078893 - OEIS Search Results

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Composite numbers n such that phi(n) - 1 is prime, where phi is Euler's totient function (A000010).

+0
3

8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 25, 26, 27, 28, 30, 33, 35, 36, 38, 39, 42, 44, 45, 49, 50, 51, 52, 54, 56, 62, 64, 65, 66, 68, 69, 70, 72, 77, 78, 80, 81, 84, 86, 90, 91, 92, 93, 95, 96, 98, 99, 102, 104, 105, 111, 112, 117, 120, 121, 122, 123, 124, 129, 130, 133 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`A078892 with the primes removed. - Ray Chandler (rayjchandler(AT)sbcglobal.net), May 26 2008`
	CROSSREFS	`Cf. A000010, A000040, A008864, A109606, A078892, A066071, A068019.` `Sequence in context: A120209 A138581 A097363 this_sequence A050704 A024884 A031009` `Adjacent sequences: A078890 A078891 A078892 this_sequence A078894 A078895 A078896`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Dec 12 2002`

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.

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