OFFSET
4,2
COMMENTS
45 years ago this was A000711, but it was dropped during the preparation of the 1973 Handbook of Integer Sequences.
MAPLE
g := proc(n, k) option remember; if k=0 then return(1) else if (n=1 and k=1) then return(0) else if (k<0 or k>binomial(n, 2)) then return(0) else g(n-1, k)+g(n, k-1)-g(n-1, k-n) end if end if end if end proc;
[seq(g(n, 6), n=4..40)];
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 30 2014
STATUS
approved