OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0,802,0,-1).
FORMULA
G.f.: -(x^2-20*x-1) / (x^4-802*x^2+1). - Colin Barker, Nov 24 2013
a(n) = 802*a(n-2) - a(n-4) for n>3. - Vincenzo Librandi, Dec 24 2013
MATHEMATICA
Denominator[Convergents[Sqrt[402], 30]] (* Vincenzo Librandi, Dec 24 2013 *)
LinearRecurrence[{0, 802, 0, -1}, {1, 20, 801, 16040}, 30] (* Harvey P. Dale, Oct 09 2017 *)
PROG
(Magma) I:=[1, 20, 801, 16040]; [n le 4 select I[n] else 802*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 24 2013
CROSSREFS
KEYWORD
nonn,frac,easy,less
AUTHOR
EXTENSIONS
a(16) from Colin Barker, Nov 24 2013
STATUS
approved