OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0, 78, 0, -1).
FORMULA
G.f.: -(x^2-2*x-1) / (x^4-78*x^2+1). - Colin Barker, Nov 22 2013
a(n) = 78*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 23 2013
MAPLE
convert(sqrt(380), confrac, 30, cvgts): denom(cvgts); # Wesley Ivan Hurt, Dec 23 2013
MATHEMATICA
Denominator[Convergents[Sqrt[380], 30]] (* Harvey P. Dale, May 29 2013 *)
CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 78 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 23 2013 *)
PROG
(Magma) I:=[1, 2, 77, 156]; [n le 4 select I[n] else 78*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 23 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 22 2013
STATUS
approved