OFFSET
0,2
COMMENTS
Diagonal sums of number triangle A110330.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1)
FORMULA
G.f.: (1-2x-4x^2+2x^3+x^4)/((1+x)^3(1-x)^3); a(n)=3a(n-2)-3a(n-4)+a(n-6); a(n)=-n(n+6)/8-(n^2-2n-8)(-1)^n/8.
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Jul 20 2005
STATUS
approved