A041049 Denominators of continued fraction convergents to sqrt(30).

1, 2, 21, 44, 461, 966, 10121, 21208, 222201, 465610, 4878301, 10222212, 107100421, 224423054, 2351330961, 4927084976, 51622180721, 108171446418, 1133336644901, 2374844736220, 24881784007101

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cofr
• frac
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (0,22,0,-1).

Crossrefs

Cf. A010485, A040024, A041048 (numerators).

Programs

Mathematica

Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[30], n]]],{n, 1, 50}] (* Vladimir Joseph Stephan Orlovsky, Mar 18 2011 *)
Denominator[Convergents[Sqrt[30], 20]] (* Vincenzo Librandi, Oct 23 2013 *)

Formula

G.f.: (1+2*x-x^2)/(1-22*x^2+x^4). [Colin Barker, Jan 02 2012]