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A042161 Denominators of continued fraction convergents to sqrt(605). 2
1, 1, 2, 5, 57, 62, 553, 615, 7318, 15251, 22569, 37820, 1837929, 1875749, 3713678, 9303105, 106047833, 115350938, 1028855337, 1144206275, 13615124362, 28374454999, 41989579361, 70364034360, 3419463228641, 3489827263001, 6909290491642, 17308408246285 (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, 0, 0, 1860498, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^22 -x^21 +2*x^20 -5*x^19 +57*x^18 -62*x^17 +553*x^16 -615*x^15 +7318*x^14 -15251*x^13 +22569*x^12 -37820*x^11 -22569*x^10 -15251*x^9 -7318*x^8 -615*x^7 -553*x^6 -62*x^5 -57*x^4 -5*x^3 -2*x^2 -x -1) / ((x^4 -11*x^2 -1)*(x^4 +11*x^2 -1)*(x^8 -11*x^6 +122*x^4 +11*x^2 +1)*(x^8 +11*x^6 +122*x^4 -11*x^2 +1)). - Colin Barker, Dec 02 2013

a(n) = 1860498*a(n-12) - a(n-24) for n>23. - Vincenzo Librandi, Jan 16 2014

MATHEMATICA

Denominator[Convergents[Sqrt[605], 30]] (* Vincenzo Librandi, Jan 16 2014_ *)

CROSSREFS

Cf. A042160, A040580.

Sequence in context: A006525 A254406 A260654 * A176142 A101151 A138788

Adjacent sequences:  A042158 A042159 A042160 * A042162 A042163 A042164

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Dec 02 2013

STATUS

approved

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Last modified November 24 00:27 EST 2017. Contains 295164 sequences.