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A041137
Denominators of continued fraction convergents to sqrt(77).
2
1, 1, 4, 9, 31, 40, 671, 711, 2804, 6319, 21761, 28080, 471041, 499121, 1968404, 4435929, 15276191, 19712120, 330670111, 350382231, 1381816804, 3114015839, 10723864321, 13837880160, 232129946881, 245967827041, 970033428004, 2186034683049, 7528137477151
OFFSET
0,3
LINKS
FORMULA
a(n) = 702*a(n-6)-a(n-12). G.f.: -(x^10-x^9+4*x^8-9*x^7+31*x^6-40*x^5-31*x^4-9*x^3-4*x^2-x-1)/((x^4-9*x^2+1)*(x^8+9*x^6+80*x^4+9*x^2+1)). [Colin Barker, Jul 18 2012]
MATHEMATICA
Denominator/@Convergents[Sqrt[77], 50] (* Vladimir Joseph Stephan Orlovsky, Jul 05 2011 *)
CoefficientList[Series[- (x^10 - x^9 + 4 x^8 - 9 x^7 + 31 x^6 - 40 x^5 - 31 x^4 - 9 x^3 - 4 x^2 - x - 1)/((x^4 - 9 x^2 + 1) (x^8 + 9 x^6 + 80 x^4 + 9 x^2 + 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 24 2013 *)
CROSSREFS
Sequence in context: A069103 A377288 A364239 * A042599 A206960 A145543
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved