OFFSET
1,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
a(n) = (n-1)*n*(n^3+n^2-2*n-2)/12.
G.f.: x^2*(1+8*x+x^2) / (x-1)^6. - R. J. Mathar, Nov 28 2011
MAPLE
seq(binomial(n^2, 3)/(2*n), n=1..29)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary Detlefs, Nov 26 2011
STATUS
approved