OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,502,0,0,0,0,0,-1).
FORMULA
a(0)=1, a(1)=1, a(2)=3, a(3)=4, a(4)=11, a(5)=15, a(6)=491, a(7)=506, a(8)=1503, a(9)=2009, a(10)=5521, a(11)=7530, a(n)=502*a(n-6)-a(n-12). - Harvey P. Dale, Aug 13 2012
G.f.: -(x^2-x-1)*(x^8+4*x^6+15*x^4+4*x^2+1) / (x^12-502*x^6+1). - Colin Barker, Nov 18 2013
MATHEMATICA
Denominator[Convergents[Sqrt[280], 30]] (* or *) LinearRecurrence[ {0, 0, 0, 0, 0, 502, 0, 0, 0, 0, 0, -1}, {1, 1, 3, 4, 11, 15, 491, 506, 1503, 2009, 5521, 7530}, 30] (* Harvey P. Dale, Aug 13 2012 *)
CoefficientList[Series[-(x^2 - x - 1) (x^8 + 4 x^6 + 15 x^4 + 4 x^2 + 1)/(x^12 - 502 x^6 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 19 2013 *)
PROG
(Magma) I:=[1, 1, 3, 4, 11, 15, 491, 506, 1503, 2009, 5521, 7530]; [n le 12 select I[n] else 502*Self(n-6)-Self(n-12): n in [1..40]]; // Vincenzo Librandi, Dec 19 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 18 2013
STATUS
approved