id:A135972 - OEIS Search Results

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Nonprime numbers of the form 2^n-1.

+0
2

0, 1, 15, 63, 255, 511, 1023, 2047, 4095, 16383, 32767, 65535, 262143, 1048575, 2097151, 4194303, 8388607, 16777215, 33554431, 67108863, 134217727, 268435455, 536870911, 1073741823, 4294967295, 8589934591, 17179869183, 34359738367 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`This sequence is a subset of A000225`
	MATHEMATICA	`k = {}; Do[If[ ! PrimeQ[2^n - 1], AppendTo[k, 2^n - 1]], {n, 1, 100}]; k`
	CROSSREFS	`Cf. A000225.` `Sequence in context: A157968 A141759 A104473 this_sequence A138104 A152099 A119496` `Adjacent sequences: A135969 A135970 A135971 this_sequence A135973 A135974 A135975`
	KEYWORD	`nonn`
	AUTHOR	`Artur Jasinski (grafix(AT)csl.pl), Dec 09 2007`

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Last modified November 30 13:13 EST 2009. Contains 167758 sequences.

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