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A158729 a(n)=34*(34*n^2-1). 1
1122, 4590, 10370, 18462, 28866, 41582, 56610, 73950, 93602, 115566, 139842, 166430, 195330, 226542, 260066, 295902, 334050, 374510, 417282, 462366, 509762, 559470, 611490, 665822, 722466, 781422, 842690, 906270, 972162, 1040366 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The identity (68*n^2-1)^2 - (1156*n^2-34) * (2*n)^2 = 1 can be written as

the Pell equation (A158730(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)= 3*a(n-1) -3*a(n-2) +a(n-3). G.f.: 34*x*(-33-36*x+x^2)/(x-1)^3.

CROSSREFS

Cf. A005843, A158730

Sequence in context: A207014 A203189 A157444 * A035859 A105310 A200072

Adjacent sequences:  A158726 A158727 A158728 * A158730 A158731 A158732

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 February 17 13:28 EST 2012. Contains 206031 sequences.