id:A111351 - OEIS Search Results

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Semiprimes of the form 2*n + 1, where n is a square.

+0
3

9, 33, 51, 129, 201, 289, 339, 393, 451, 579, 649, 723, 1059, 1569, 1923, 2049, 3043, 3873, 4609, 4803, 5001, 5619, 5833, 6051, 6499, 6729, 7201, 7939, 8193, 9249, 9523, 10083, 11553, 12169, 13123, 13449, 14113, 14451, 14793, 15843, 16201, 16563 (list; graph; listen)

	OFFSET	`0,1`
	FORMULA	`a(n) = 2*A111350(n) + 1.`
	MATHEMATICA	`Select[2Range[100]^2 + 1, Plus @@ Last /@ FactorInteger[ # ] == 2 &] (Chandler)`
	CROSSREFS	`Cf. A111350, A112777.` `Sequence in context: A145849 A111045 A020226 this_sequence A065064 A075812 A146262` `Adjacent sequences: A111348 A111349 A111350 this_sequence A111352 A111353 A111354`
	KEYWORD	`nonn`
	AUTHOR	`Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Oct 29 2005`
	EXTENSIONS	`Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 10 2005`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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