id:A158555 - OEIS Search Results

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a(n)=14*(14*n^2+1).

+0
2

14, 210, 798, 1778, 3150, 4914, 7070, 9618, 12558, 15890, 19614, 23730, 28238, 33138, 38430, 44114, 50190, 56658, 63518, 70770, 78414, 86450, 94878, 103698, 112910, 122514, 132510, 142898, 153678, 164850, 176414, 188370, 200718, 213458, 226590 (list; graph; listen)

	OFFSET	`0,1`
	COMMENT	`The identity (28n^2+1)^2 - (196n^2+14) * (2n)^2 = 1 can be written` `in Pell-type form as (A158556(n))^2 - a(n) (A005843(n))^2 =1.`
	LINKS	`Vincenzo Librandi, X^2-AY^2=1` `Edward Everett Withford, Pell Equation` `Wolfram MathWorld, Pell Equation`
	FORMULA	`a(n)= 3a(n-1) -3a(n-2) +a(n-3). G.f.: 14(1+12x+15*x^2)/(1-x)^3.`
	CROSSREFS	`Cf. A005843, A158556` `Sequence in context: A063071 A160682 A097261 this_sequence A097183 A004369 A121972` `Adjacent sequences: A158552 A158553 A158554 this_sequence A158556 A158557 A158558`
	KEYWORD	`nonn,easy`
	AUTHOR	`Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 21 2009`
	EXTENSIONS	`Comment rewritten, a(0) added - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 16 2009`

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

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