A041431 Denominators of continued fraction convergents to sqrt(231).

1, 5, 151, 760, 22951, 115515, 3488401, 17557520, 530214001, 2668627525, 80589039751, 405613826280, 12249003828151, 61650632967035, 1861767992839201, 9370490597163040, 282976485907730401, 1424252920135815045

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0,152,0,-1).

Formula

a(n) = 152*a(n-2)-a(n-4). G.f.: -(x^2-5*x-1)/(x^4-152*x^2+1). [Colin Barker, Jul 15 2012]

Mathematica

CoefficientList[Series[- (x^2 - 5 x - 1)/(x^4 - 152 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 25 2013 *)

Crossrefs

Cf. A041430.

Sequence in context: A324097 A082441 A096065 * A107691 A181979 A258486

Adjacent sequences: A041428 A041429 A041430 * A041432 A041433 A041434

Keyword

nonn,cofr,frac,easy

Author

N. J. A. Sloane.

Status

approved