login
A042921
Denominators of continued fraction convergents to sqrt(992).
2
1, 2, 125, 252, 15749, 31750, 1984249, 4000248, 249999625, 503999498, 31497968501, 63499936500, 3968494031501, 8000487999502, 499998750000625, 1007997988000752, 62995874006047249, 126999746000095250, 7936980126011952749, 16000959998024000748
OFFSET
0,2
FORMULA
G.f.: -(x^2-2*x-1) / (x^4-126*x^2+1). - Colin Barker, Dec 25 2013
a(n) = 126*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Feb 01 2014
MATHEMATICA
Denominator[Convergents[Sqrt[992], 30]] (* Vincenzo Librandi, Feb 01 2014 *)
PROG
(Magma) I:=[1, 2, 125, 252]; [n le 4 select I[n] else 126*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Feb 01 2014
CROSSREFS
Sequence in context: A065705 A012870 A183720 * A123006 A028481 A049659
KEYWORD
nonn,frac,easy
EXTENSIONS
More terms from Colin Barker, Dec 25 2013
STATUS
approved