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A042200
Numerators of continued fraction convergents to sqrt(626).
3
25, 1251, 62575, 3130001, 156562625, 7831261251, 391719625175, 19593812520001, 980082345625225, 49023711093781251, 2452165637034687775, 122657305562828170001, 6135317443778443187825, 306888529494484987561251
OFFSET
0,1
FORMULA
a(n) = 50*a(n-1)+a(n-2) for n>1; a(0)=25, a(1)=1251. G.f.: (25+x)/(1-50*x-x^2). [Philippe Deléham, Nov 23 2008]
MATHEMATICA
Numerator[Convergents[Sqrt[626], 30]] (* Harvey P. Dale, Jul 15 2012 *)
CoefficientList[Series[(25 + x)/(1 - 50 x - x^2), {x, 0, 20}], x] (* Vincenzo Librandi, Nov 19 2013 *)
PROG
(Magma) I:=[25, 1251]; [n le 2 select I[n] else 50*Self(n-1)+Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 19 2013
CROSSREFS
Cf. A042201.
Sequence in context: A096330 A174751 A042203 * A104593 A046910 A278851
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved