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A042200
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Numerators of continued fraction convergents to sqrt(626).
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3
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25, 1251, 62575, 3130001, 156562625, 7831261251, 391719625175, 19593812520001, 980082345625225, 49023711093781251, 2452165637034687775, 122657305562828170001, 6135317443778443187825, 306888529494484987561251
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OFFSET
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0,1
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LINKS
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FORMULA
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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]
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MATHEMATICA
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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 *)
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn,cofr,frac,easy
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AUTHOR
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STATUS
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approved
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