login
A041385
Denominators of continued fraction convergents to sqrt(207).
2
1, 2, 3, 5, 13, 18, 31, 80, 2271, 4622, 6893, 11515, 29923, 41438, 71361, 184160, 5227841, 10639842, 15867683, 26507525, 68882733, 95390258, 164272991, 423936240, 12034487711, 24492911662, 36527399373, 61020311035, 158568021443, 219588332478
OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,2302,0,0,0,0,0,0,0,-1).
FORMULA
G.f.: -(x^14 -2*x^13 +3*x^12 -5*x^11 +13*x^10 -18*x^9 +31*x^8 -80*x^7 -31*x^6 -18*x^5 -13*x^4 -5*x^3 -3*x^2 -2*x -1) / ((x^8 -48*x^4 +1)*(x^8 +48*x^4 +1)). - Colin Barker, Nov 16 2013
a(n) = 2302*a(n-8) - a(n-16) for n>15. - Vincenzo Librandi, Dec 16 2013
MATHEMATICA
Denominator[Convergents[Sqrt[207], 40]] (* Harvey P. Dale, May 03 2012 *)
CoefficientList[Series[-(x^14 - 2 x^13 + 3 x^12 - 5 x^11 + 13 x^10 - 18 x^9 + 31 x^8 - 80 x^7 - 31 x^6 - 18 x^5 - 13 x^4 - 5 x^3 - 3 x^2 - 2 x - 1)/((x^8 - 48 x^4 + 1) (x^8 + 48 x^4 + 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 16 2013 *)
PROG
(Magma) I:=[1, 2, 3, 5, 13, 18, 31, 80, 2271, 4622, 6893, 11515, 29923, 41438, 71361, 184160]; [n le 16 select I[n] else 2302*Self(n-8)-Self(n-16): n in [1..40]]; // Vincenzo Librandi, Dec 16 2013
CROSSREFS
Sequence in context: A042261 A112596 A179238 * A108282 A042047 A273939
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 16 2013
STATUS
approved