id:A158590 - OEIS Search Results

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a(n)=18*(18*n^2+1).

+0
2

18, 342, 1314, 2934, 5202, 8118, 11682, 15894, 20754, 26262, 32418, 39222, 46674, 54774, 63522, 72918, 82962, 93654, 104994, 116982, 129618, 142902, 156834, 171414, 186642, 202518, 219042, 236214, 254034, 272502, 291618, 311382, 331794 (list; graph; listen)

	OFFSET	`0,1`
	COMMENT	`The identity (36n^2+1)^2 - (324n^2+18)(2n)^2 = 1 can be written in` `Pell-format as (A158591(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.: -18(1+16x+19*x^2)/(x-1)^3.`
	CROSSREFS	`Cf. A005843, A158591` `Sequence in context: A166787 A068771 A039646 this_sequence A143168 A127585 A086502` `Adjacent sequences: A158587 A158588 A158589 this_sequence A158591 A158592 A158593`
	KEYWORD	`nonn,easy`
	AUTHOR	`Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 22 2009`
	EXTENSIONS	`Comment rewritten, formula replaced by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 28 2009`

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Last modified December 20 16:54 EST 2009. Contains 171081 sequences.

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