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A041239 Denominators of continued fraction convergents to sqrt(131). 2
1, 2, 9, 101, 413, 927, 20807, 42541, 190971, 2143222, 8763859, 19670940, 441524539, 902720018, 4052404611, 45479170739, 185969087567, 417417345873, 9369150696773, 19155718739419, 85992025654449 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,21220,0,0,0,0,0,-1).

FORMULA

a(n) = 21220*a(n-6)-a(n-12). G.f.: -(x^10-2*x^9+9*x^8-101*x^7+413*x^6-927*x^5-413*x^4-101*x^3-9*x^2-2*x-1)/(x^12-21220*x^6+1). [Colin Barker, Jul 19 2012]

MATHEMATICA

Denominator[Convergents[Sqrt[131], 30]] (* Vincenzo Librandi, Oct 24 2013 *)

CROSSREFS

Cf. A041238.

Sequence in context: A322645 A277180 A013520 * A098610 A226391 A125815

Adjacent sequences:  A041236 A041237 A041238 * A041240 A041241 A041242

KEYWORD

nonn,cofr,frac,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified July 11 17:01 EDT 2020. Contains 335626 sequences. (Running on oeis4.)