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1, 63, 3905, 242047, 15003009, 929944511, 57641556673, 3572846569215, 221458845734657, 13726875588979519, 850844827670995521, 52738652440012742783, 3268945606453119057025, 202621888947653368792767, 12559288169148055746094529, 778473244598231802889068031
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (1/2-2/sqrt(15))*(31-8*sqrt(15))^n+((15+4*sqrt(15))*(31+8*sqrt(15))^n)/30.
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MATHEMATICA
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a[c_, p_, n_] := Module[{},
l := Length[ContinuedFraction[ Sqrt[ c]][[2]]];
d := Denominator[Convergents[Sqrt[c], n l]] ;
t := Table[d[[i + 1]], {i, p, Length[d] - 1, l}] ;
Return[t];
];
a[60, 1, 20]
CoefficientList[Series[(1 + x)/(x^2 - 62 x + 1), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 08 2015 *)
LinearRecurrence[{62, -1}, {1, 63}, 30] (* Harvey P. Dale, Dec 24 2015 *)
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PROG
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(PARI) Vec((x+1)/(x^2-62*x+1) + O(x^100)) \\ Colin Barker, Jun 07 2015
(Magma) I:=[1, 63]; [n le 2 select I[n] else 62*Self(n-1)-Self(n-2): n in [1..45]]; // Vincenzo Librandi, Jun 08 2015
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CROSSREFS
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Cf. A041105 (denominators of continued fraction convergents to sqrt(60)).
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KEYWORD
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nonn,easy,frac
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AUTHOR
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STATUS
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approved
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