OFFSET
0,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (-1,-1,-1).
FORMULA
From Luce ETIENNE, Mar 25 2017: (Start)
a(n)= (6*(-1)^n-(-1)^((2*n+1-(-1)^n)/4)-(-1)^((2*n-1+(-1)^n)/4))/2.
a(n) = 3*cos(n*Pi)-cos(n*Pi/2). (End)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Sep 17 2007
EXTENSIONS
Better name from Joerg Arndt, Apr 02 2017
STATUS
approved