OFFSET
0,3
COMMENTS
Diagonal sums of number triangle A115633.
LINKS
Index entries for linear recurrences with constant coefficients, signature (-1,-1,0,1,1,1).
FORMULA
G.f.: (1+2x-3x^2-4x^3-5x^4-4x^5)/((1-x^3)*(1+x+x^2+x^3)); a(n)=sum{k=0..floor(n/2), A115633(n-k, k)}.
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Jan 27 2006
STATUS
approved