login
A041852
Numerators of continued fraction convergents to sqrt(448).
2
21, 127, 5355, 32257, 1360149, 8193151, 345472491, 2081028097, 87748652565, 528572943487, 22287812279019, 134255446617601, 5661016570218261, 34100354867927167, 1437875921023159275
OFFSET
0,1
FORMULA
G.f.: (21 + 127*x + 21*x^2 - x^3)/(1 - 254*x^2 + x^4). - Vincenzo Librandi, Nov 10 2013
a(n) = 254*a(n-2) - a(n-4). - Vincenzo Librandi, Nov 10 2013
MATHEMATICA
Numerator[Convergents[Sqrt[448], 30]] (* or *) CoefficientList[Series[(21 + 127 x + 21 x^2 - x^3)/(1 - 254 x^2 + x^4), {x, 0, 25}], x] (* Vincenzo Librandi, Nov 10 2013 *)
PROG
(Magma) I:=[21, 127, 5355, 32257]; [n le 4 select I[n] else 254*Self(n-2)-Self(n-4): n in [1..20]]; // Vincenzo Librandi, Nov 10 2013
CROSSREFS
Cf. A041853.
Sequence in context: A316310 A317265 A213565 * A220712 A295916 A124117
KEYWORD
nonn,cofr,frac,easy,less
AUTHOR
STATUS
approved