login
A041465
Denominators of continued fraction convergents to sqrt(248).
2
1, 1, 3, 4, 123, 127, 377, 504, 15497, 16001, 47499, 63500, 1952499, 2015999, 5984497, 8000496, 245999377, 253999873, 753999123, 1007998996, 30993969003, 32001967999, 94997905001, 126999873000, 3904994095001, 4031993968001, 11968982031003, 16000975999004
OFFSET
0,3
FORMULA
G.f.: -(x^2-x-1)*(x^4+4*x^2+1) / (x^8-126*x^4+1). - Colin Barker, Nov 18 2013
a(n) = 126*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 18 2013
MATHEMATICA
Denominator[Convergents[Sqrt[248], 30]] (* Vincenzo Librandi, Dec 18 2013 *)
LinearRecurrence[{0, 0, 0, 126, 0, 0, 0, -1}, {1, 1, 3, 4, 123, 127, 377, 504}, 30] (* Harvey P. Dale, Apr 19 2019 *)
PROG
(Magma) I:=[1, 1, 3, 4, 123, 127, 377, 504]; [n le 8 select I[n] else 126*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 18 2013
CROSSREFS
Sequence in context: A041351 A266516 A066496 * A004124 A175504 A308944
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 18 2013
STATUS
approved