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A158683 a(n)=32*(32*n^2-1). 1
992, 4064, 9184, 16352, 25568, 36832, 50144, 65504, 82912, 102368, 123872, 147424, 173024, 200672, 230368, 262112, 295904, 331744, 369632, 409568, 451552, 495584, 541664, 589792, 639968, 692192, 746464, 802784, 861152, 921568, 984032, 1048544 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The identity (64*n^2-1)^2 - (1024*n^2-32) * (2*n)^2 = 1 can be written as

the Pell equation (A158684(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.: 32*x*(-31-34*x+x^2)/(x-1)^3.

CROSSREFS

Cf. A005843, A158684

Sequence in context: A161926 A172698 A109149 * A030645 A010463 A183973

Adjacent sequences:  A158680 A158681 A158682 * A158684 A158685 A158686

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 24 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 14 11:36 EST 2012. Contains 205623 sequences.