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A042524
Numerators of continued fraction convergents to sqrt(791).
2
28, 225, 12628, 101249, 5682572, 45561825, 2557144772, 20502720001, 1150709464828, 9226178438625, 517816702027828, 4151759794661249, 233016365203057772, 1868282681419123425, 104856846524673969572
OFFSET
0,1
FORMULA
G.f.: (28 +225*x +28*x^2 -x^3)/(1 -450*x^2 +x^4). - Vincenzo Librandi, Nov 26 2013
a(n) = 450*a(n-2) - a(n-4). - Vincenzo Librandi, Nov 26 2013
MATHEMATICA
Numerator[Convergents[Sqrt[791], 30]] (* or *) CoefficientList[Series[(28 + 225 x + 28 x^2 - x^3)/(1 - 450 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 25 2013 *)
LinearRecurrence[{0, 450, 0, -1}, {28, 225, 12628, 101249}, 20] (* Harvey P. Dale, Jul 20 2024 *)
PROG
(Magma) I:=[28, 225, 12628, 101249]; [n le 4 select I[n] else 450*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Nov 26 2013
CROSSREFS
Cf. A042525.
Sequence in context: A133071 A339137 A135180 * A125365 A126523 A115224
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved