OFFSET
0,4
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,2,-6,0,6,-2,-2,1).
FORMULA
Let b(n) = floor(n^2/2), for n => 0, then a(n) = b(n)*(b(n)- 1)/2.
G.f. -x^2*(1+4*x+14*x^2+4*x^3+x^4) / ( (1+x)^3*(x-1)^5 ). - R. J. Mathar, Aug 14 2013
a(n) = binomial(floor(n^2/2), 2). - Wesley Ivan Hurt, Sep 27 2013
MAPLE
MATHEMATICA
Table[Binomial[Floor[n^2/2], 2], {n, 0, 50}] (* Wesley Ivan Hurt, Sep 27 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Richard R. Forberg, Aug 01 2013
STATUS
approved