A081234 Let p = n-th prime, take smallest solution (x,y) to the Pellian equation x^2 - p*y^2 = 1 with x and y >= 1; sequence gives value of y.

2, 1, 4, 3, 3, 180, 8, 39, 5, 1820, 273, 12, 320, 531, 7, 9100, 69, 226153980, 5967, 413, 267000, 9, 9, 53000, 6377352, 20, 22419, 93, 15140424455100, 113296, 419775, 927, 519712, 6578829, 2113761020, 140634693, 3726964292220, 5019135, 13, 190060

Offset

1,1

Links

Table of n, a(n) for n=1..40.

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Mathematica

PellSolve[(m_Integer)?Positive] := Module[{cf, n, s}, cf = ContinuedFraction[ Sqrt[m]]; n = Length[Last[cf]]; If[OddQ[n], n = 2*n]; s = FromContinuedFraction[ ContinuedFraction[ Sqrt[m], n]]; {Numerator[s], Denominator[s]}]; Table[ PellSolve[ Prime[n]][[2]], {n, 40}] (* Robert G. Wilson v, Jul 22 2005 *)

Crossrefs

Values of x are in A081233. Equals A002349(p). Cf. A082393.

Sequence in context: A348684 A159573 A102916 * A105239 A261366 A283166

Adjacent sequences: A081231 A081232 A081233 * A081235 A081236 A081237

Keyword

easy,nonn

Author

N. J. A. Sloane, Apr 18 2003

Extensions

More terms (a(8) - a(40)) from Robert G. Wilson v, Jul 22 2005

Status

approved