OFFSET
0,3
COMMENTS
Antidiagonal sums of triangle T(n,k) = A104040(n,k)*(-1)^floor(k/2). - Philippe Deléham, Dec 11 2011
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,0,-1).
FORMULA
a(n) = 2*a(n-1) - a(n-4), n>3.
a(n+1)-a(n) = A081172(n+2). - Philippe Deléham, Dec 11 2011
MATHEMATICA
CoefficientList[Series[(1-x+x^2)/((1-x)(1-x-x^2-x^3)), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, 0, 0, -1}, {1, 1, 3, 6}, 40] (* Harvey P. Dale, Apr 21 2014 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Philippe Deléham, Dec 08 2011
STATUS
approved