OFFSET
0,14
COMMENTS
Diagonal sums of number triangle A124749.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,1,-1).
FORMULA
a(n)=sum{k=0..floor(n/2), C(floor(k/3),n-2k)*(-1)^n}
MATHEMATICA
CoefficientList[Series[(1+x^2+x^4)/(1-x^6+x^7), {x, 0, 100}], x] (* or *) LinearRecurrence[{0, 0, 0, 0, 0, 1, -1}, {1, 0, 1, 0, 1, 0, 1}, 100] (* Harvey P. Dale, Mar 10 2017 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Nov 06 2006
STATUS
approved