OFFSET
0,4
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1,0,2).
FORMULA
Recurrence: a(n) = -a(n-1) + 2a(n-3), starting 1,1,0.
O.g.f.: (1+x)^2/((1-x)(1+2x+2x^2)). - R. J. Mathar, Jun 12 2008
a(4n) = a(4n+1) = (-1)^n*A109499(n). - Paul Curtz, Nov 01 2009
a(n) = (1/5) * (A137429(n-1) + 4) = A077973(n-2) + 2*A077973(n-1) + A077973(n). - Ralf Stephan, Aug 18 2013
MATHEMATICA
LinearRecurrence[{-1, 0, 2}, {1, 1, 0}, 50] (* Harvey P. Dale, Sep 17 2012 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Paul Curtz, Apr 23 2008
EXTENSIONS
More terms from R. J. Mathar, Jun 12 2008
STATUS
approved