A121763 - OEIS

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A121763

Numbers n such that 6n-1 is prime while 6n+1 is composite.

4, 8, 9, 14, 15, 19, 22, 28, 29, 39, 42, 43, 44, 49, 53, 59, 60, 64, 65, 67, 74, 75, 78, 80, 82, 84, 85, 93, 94, 98, 99, 108, 109, 113, 114, 117, 120, 124, 127, 129, 133, 140, 144, 148, 152, 155, 157, 158, 159, 162, 163, 164, 169, 183, 184, 185, 194, 197, 198, 199 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Entries of A024898 which are not in A002822 or equivalently,entries of A046954 which are not in A060461.`
	MATHEMATICA	`Select[Range[200], PrimeQ[6# - 1] && ! PrimeQ[6# + 1] &] (Chandler)`
	CROSSREFS	`Cf. A121762.` `Sequence in context: A046954 A112775 A107747 * A110087 A085711 A122785` `Adjacent sequences: A121760 A121761 A121762 * A121764 A121765 A121766`
	KEYWORD	`nonn`
	AUTHOR	`Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 20 2006`
	EXTENSIONS	`Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 22 2006`

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Last modified February 17 13:06 EST 2012. Contains 206025 sequences.