A117719 - OEIS

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A117719

a(2n) = A001653(n) (Numbers n such that 2*n^2 - 1 is a square), a(2n+1) = A038725(n+1).

1, 2, 5, 11, 29, 64, 169, 373, 985, 2174, 5741, 12671, 33461, 73852, 195025, 430441, 1136689, 2508794, 6625109, 14622323, 38613965, 85225144, 225058681, 496728541, 1311738121, 2895146102, 7645370045, 16874148071, 44560482149 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	FORMULA	`G.f. (1+2x-x^2-x^3)/((x^2+2x-1)(x^2-2x-1))`
	CROSSREFS	`Cf. A001653, A038725.` `Sequence in context: A202476 A127331 A040998 * A192785 A014211 A160911` `Adjacent sequences: A117716 A117717 A117718 * A117720 A117721 A117722`
	KEYWORD	`nonn`
	AUTHOR	`Creighton Dement (creighton.k.dement(AT)uni-oldenburg.de), Apr 13 2006`

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Last modified February 16 21:51 EST 2012. Contains 205978 sequences.