A041478 Numerators of continued fraction convergents to sqrt(255).

15, 16, 495, 511, 15825, 16336, 505905, 522241, 16173135, 16695376, 517034415, 533729791, 16528928145, 17062657936, 528408666225, 545471324161, 16892548391055, 17438019715216, 540033139847535

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cofr
• frac
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,32,0,-1).

Crossrefs

Cf. A041479, A176110.

Programs

Mathematica

Numerator[Convergents[Sqrt[255],50]] (* Harvey P. Dale, Jun 20 2012 *)
CoefficientList[Series[- (x^3 - 15 x^2 - 16 x - 15)/(x^4 - 32 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 27 2013 *)

Formula

a(n) = 32*a(n-2)-a(n-4). G.f.: -(x^3-15*x^2-16*x-15)/(x^4-32*x^2+1). [Colin Barker, Jul 16 2012]