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A158676 62*n^2+1. 2
1, 63, 249, 559, 993, 1551, 2233, 3039, 3969, 5023, 6201, 7503, 8929, 10479, 12153, 13951, 15873, 17919, 20089, 22383, 24801, 27343, 30009, 32799, 35713, 38751, 41913, 45199, 48609, 52143, 55801, 59583, 63489, 67519, 71673, 75951, 80353 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

The identity (62*n^2+1)^2 - (961*n^2+31)*(2*n)^2 = 1 can be written as

the Pell equation (a(n))^2 - A158675(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.: -(1+60*x+63*x^2)/(x-1)^3.

CROSSREFS

Cf. A005843, A158676.

Sequence in context: A083079 A184457 A184449 * A157948 A158684 A063398

Adjacent sequences:  A158673 A158674 A158675 * A158677 A158678 A158679

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 24 2009

EXTENSIONS

Comment rewritten, a(0) added and formula replaced by R. J. Mathar, Oct 22 2009

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Last modified February 17 17:51 EST 2012. Contains 206061 sequences.