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A041935 Denominators of continued fraction convergents to sqrt(490). 2
1, 7, 15, 22, 103, 434, 1839, 2273, 6385, 46968, 2072977, 14557807, 31188591, 45746398, 214174183, 902443130, 3823946703, 4726389833, 13276726369, 97663474416, 4310469600673, 30270950679127, 64852370958927, 95123321638054, 445345657511143, 1876505951682626 (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 (0,0,0,0,0,0,0,0,0,2079362,0,0,0,0,0,0,0,0,0,-1).

FORMULA

G.f.: -(x^18 -7*x^17 +15*x^16 -22*x^15 +103*x^14 -434*x^13 +1839*x^12 -2273*x^11 +6385*x^10 -46968*x^9 -6385*x^8 -2273*x^7 -1839*x^6 -434*x^5 -103*x^4 -22*x^3 -15*x^2 -7*x -1) / ((x^10 -1442*x^5 +1)*(x^10 +1442*x^5 +1)). - Colin Barker, Nov 27 2013

a(n) = 2079362*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Dec 27 2013

MATHEMATICA

Denominator[Convergents[Sqrt[490], 30]] (* Vincenzo Librandi, Dec 27 2013 *)

CROSSREFS

Cf. A041934, A040467.

Sequence in context: A022389 A041225 A128840 * A041092 A004215 A206906

Adjacent sequences:  A041932 A041933 A041934 * A041936 A041937 A041938

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 27 2013

STATUS

approved

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Last modified October 14 07:19 EDT 2019. Contains 327995 sequences. (Running on oeis4.)