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A042202
Numerators of continued fraction convergents to sqrt(627).
2
25, 626, 31325, 783751, 39218875, 981255626, 49102000175, 1228531260001, 61475665000225, 1538120156265626, 76967483478281525, 1925725207113303751, 96363227839143469075, 2411006421185700030626, 120646684287124145000375
OFFSET
0,1
FORMULA
G.f.: (25 +626*x +25*x^2 -x^3)/(1 -1252*x^2 +x^4). - Vincenzo Librandi, Nov 19 2013
a(n) = 1252*a(n-2) - a(n-4). - Vincenzo Librandi, Nov 19 2013
MATHEMATICA
Numerator[Convergents[Sqrt[627], 20]] (* Harvey P. Dale, Oct 20 2012 *)
CoefficientList[Series[(25 + 626 x + 25 x^2 - x^3)/(x^4 - 1252 x^2 + 1), {x, 0, 20}], x] (* Vincenzo Librandi, Nov 19 2013 *)
PROG
(Magma) I:=[25, 626, 31325, 783751]; [n le 4 select I[n] else 1252*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Nov 19 2013
CROSSREFS
Cf. A042203.
Sequence in context: A207216 A171299 A009969 * A203341 A260048 A152256
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved