A087781 - OEIS

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A087781

Number of non-congruent solutions to x^2 - x - 1 == 0 mod n.

1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,11`
	COMMENTS	`Sequence A089270 gives the positions of the nonzero terms. The term a(n) gives the number of primitive solutions (x,y) of the equation x^2 + xy - y^2 = n.`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..10000`
	CROSSREFS	`Cf. A000086, A034444.` `Sequence in context: A102354 A193138 A162641 * A181009 A056626 A091398` `Adjacent sequences: A087778 A087779 A087780 * A087782 A087783 A087784`
	KEYWORD	`mult,nonn`
	AUTHOR	`Yuval Dekel (dekelyuval(AT)hotmail.com), Oct 06 2003`
	EXTENSIONS	`More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jun 17 2005`

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Last modified February 17 04:46 EST 2012. Contains 205985 sequences.