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A041887 Denominators of continued fraction convergents to sqrt(465). 2
1, 1, 2, 7, 16, 39, 94, 321, 415, 736, 31327, 32063, 63390, 222233, 507856, 1237945, 2983746, 10189183, 13172929, 23362112, 994381633, 1017743745, 2012125378, 7054119879, 16120365136, 39294850151, 94710065438, 323425046465, 418135111903, 741560158368 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,31742,0,0,0,0,0,0,0,0,0,-1).

FORMULA

G.f.: -(x^18 -x^17 +2*x^16 -7*x^15 +16*x^14 -39*x^13 +94*x^12 -321*x^11 +415*x^10 -736*x^9 -415*x^8 -321*x^7 -94*x^6 -39*x^5 -16*x^4 -7*x^3 -2*x^2 -x -1) / (x^20 -31742*x^10 +1). - Colin Barker, Nov 26 2013

a(n) = 31742*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Dec 26 2013

MATHEMATICA

Denominator[Convergents[Sqrt[465], 30]] (* Vincenzo Librandi, Dec 26 2013 *)

PROG

(MAGMA) I:=[1, 1, 2, 7, 16, 39, 94, 321, 415, 736, 31327, 32063, 63390, 222233, 507856, 1237945, 2983746, 10189183, 13172929, 23362112]; [n le 20 select I[n] else 31742*Self(n-10)-Self(n-20): n in [1..40]]; // Vincenzo Librandi, Dec 26 2013

CROSSREFS

Cf. A041886, A040443.

Sequence in context: A260505 A042243 A293378 * A129441 A093971 A065497

Adjacent sequences:  A041884 A041885 A041886 * A041888 A041889 A041890

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 26 2013

STATUS

approved

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Last modified June 25 17:47 EDT 2019. Contains 324353 sequences. (Running on oeis4.)