id:A111350 - OEIS Search Results

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Squares n such that 2*n + 1 is a semiprime.

+0
3

4, 16, 25, 64, 100, 144, 169, 196, 225, 289, 324, 361, 529, 784, 961, 1024, 1521, 1936, 2304, 2401, 2500, 2809, 2916, 3025, 3249, 3364, 3600, 3969, 4096, 4624, 4761, 5041, 5776, 6084, 6561, 6724, 7056, 7225, 7396, 7921, 8100, 8281, 10816, 11664, 12321 (list; graph; listen)

	OFFSET	`0,1`
	FORMULA	`a(n) = (A111351(n)-1)/2 = A112777(n)^2.`
	MATHEMATICA	`Select[Range[111]^2, Plus @@ Last /@ FactorInteger[2# + 1] == 2 &] (Chandler)`
	CROSSREFS	`Cf. A111351, A112777.` `Sequence in context: A087055 A135556 A075576 this_sequence A105078 A050707 A046346` `Adjacent sequences: A111347 A111348 A111349 this_sequence A111351 A111352 A111353`
	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 July 26 23:19 EDT 2008. Contains 142293 sequences.

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