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A041614
Numerators of continued fraction convergents to sqrt(326).
2
18, 325, 11718, 211249, 7616682, 137311525, 4950831582, 89252280001, 3218032911618, 58013844689125, 2091716441720118, 37708909795651249, 1359612469085165082, 24510733353328622725, 883746013188915583182, 15931938970753809120001, 574433548960326043903218
OFFSET
0,1
FORMULA
G.f.: -(x^3-18*x^2-325*x-18)/(x^4-650*x^2+1). - Vincenzo Librandi, Nov 05 2013
a(n) = 650*a(n-2)-a(n-4). - Vincenzo Librandi, Nov 05 2013
MATHEMATICA
Numerator[Convergents[Sqrt[326], 30]] (*or *) CoefficientList[Series[-(x^3 - 18 x^2 - 325 x - 18)/(x^4 - 650 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 05 2013 *)
LinearRecurrence[{0, 650, 0, -1}, {18, 325, 11718, 211249}, 30] (* Harvey P. Dale, Jan 01 2014 *)
PROG
(Magma) I:=[18, 325, 11718, 211249]; [n le 4 select I[n] else 650*Self(n-2)-Self(n-4): n in [1..20]]; // Vincenzo Librandi, Nov 05 2013
CROSSREFS
Cf. A041615.
Sequence in context: A285875 A223311 A041145 * A222812 A166787 A280806
KEYWORD
nonn,cofr,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 09 2013
STATUS
approved