OFFSET
0,7
LINKS
Paolo Xausa, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (2,-1,1,-2,1,-1,2,-1,1,-2,1).
FORMULA
From R. J. Mathar, Apr 15 2010: (Start)
a(n) = +2*a(n-1) -a(n-2) +a(n-3) -2*a(n-4) +a(n-5) -a(n-6) +2*a(n-7) -a(n-8) +a(n-9) -2*a(n-10) +a(n-11).
G.f.: x^4*(x^4+1-x^3-x+x^2) / ((1-x)^3*(1+x+x^2)*(x^2+1)*(x^4-x^2+1)). (End)
MAPLE
seq(floor(binomial(n-1, 2)/6), n=1..53); # Zerinvary Lajos, Jan 12 2009
MATHEMATICA
Table[Floor[n*(n - 1)/12], {n, 0, 100}] (* Paolo Xausa, Sep 02 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved