id:A158737 - OEIS Search Results

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a(n)=36*(36*n^2-1).

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1260, 5148, 11628, 20700, 32364, 46620, 63468, 82908, 104940, 129564, 156780, 186588, 218988, 253980, 291564, 331740, 374508, 419868, 467820, 518364, 571500, 627228, 685548, 746460, 809964, 876060, 944748, 1016028, 1089900, 1166364 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`The identity (72n^2-1)^2 - (1296n^2-36) * (2n)^2 = 1 can be written as` `the Pell equation (A158738(n))^2 - a(n) (A005843(n))^2 = 1.`
	LINKS	`Wolfram MathWorld, 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.: 36x(-35-38*x+x^2)/(x-1)^3.`
	CROSSREFS	`Cf. A005843, A158738` `Sequence in context: A099592 A014575 A144563 this_sequence A047634 A101469 A094208` `Adjacent sequences: A158734 A158735 A158736 this_sequence A158738 A158739 A158740`
	KEYWORD	`nonn,easy`
	AUTHOR	`Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 25 2009`
	EXTENSIONS	`Comment rewritten and formula replaced by R. J. Mathar, (mathar(AT)strw.leidenuniv.nl), Oct 22 2009`

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Last modified December 20 13:54 EST 2009. Contains 171081 sequences.

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