OFFSET
0,2
COMMENTS
a(n)/A083335(n) converges to sqrt(11).
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,12,0,-25).
FORMULA
G.f.: (1 + 6*x + 5*x^2 - 25*x^3) / (1 - 12*x^2 + 25*x^4).
a(n) = (x^(n+1) + (-1)^(n+1)*(x-2)^(n+1))/2^ceiling(n/2 + 1) where x = 1 + sqrt(11). - Ben Paul Thurston, Aug 30 2006 [edited by Jon E. Schoenfield, Jun 25 2019]
MATHEMATICA
CoefficientList[Series[(1+6x+5x^2-25x^3)/(1-12x^2+25x^4), {x, 0, 10}], x]
LinearRecurrence[{0, 12, 0, -25}, {1, 6, 17, 47}, 30] (* Harvey P. Dale, Oct 15 2012 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Apr 26 2003
STATUS
approved