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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
OFFSET
0,3
LINKS
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
Sequence in context: A254406 A260654 A339167 * A176142 A101151 A138788
KEYWORD
nonn,frac,easy
EXTENSIONS
More terms from Colin Barker, Dec 02 2013
STATUS
approved