id:A158540 - OEIS Search Results

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a(n)=22*n^2-1.

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21, 87, 197, 351, 549, 791, 1077, 1407, 1781, 2199, 2661, 3167, 3717, 4311, 4949, 5631, 6357, 7127, 7941, 8799, 9701, 10647, 11637, 12671, 13749, 14871, 16037, 17247, 18501, 19799, 21141, 22527, 23957, 25431, 26949, 28511, 30117, 31767 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`From the Pell-type identity (22n^2-1)^2 - (121n^2-11) * (2n)^2 = 1 we derive` `(a(n))^2 - A158539(n) (A005843(n))^2 =1.`
	LINKS	`Philippe Chevanne, Pell Equation` `Vincenzo Librandi, X^2-AY^2=1` `Edward Everett Withford, Pell Equation`
	FORMULA	`a(n)= 3a(n-1) -3a(n-2) +a(n-3). G.f.: x(-21-24x+x^2)/(x-1)^3.`
	CROSSREFS	`Cf. A005843, A158539` `Sequence in context: A041858 A063651 A045016 this_sequence A020248 A065827 A143843` `Adjacent sequences: A158537 A158538 A158539 this_sequence A158541 A158542 A158543`
	KEYWORD	`nonn,easy`
	AUTHOR	`Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 21 2009`
	EXTENSIONS	`Comment rewritten - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 16 2009`

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

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