OFFSET
0,5
LINKS
A. Umar, Combinatorial Results for Semigroups of Orientation-Preserving Partial Transformations, J. Int. Seq. 14 (2011) # 11.7.5, Corollary 9, Table 2.1
EXAMPLE
1 ;
1 1;
1 4 4;
1 9 27 24;
1 16 96 208 128;
1 25 250 950 1325 610;
1 36 540 3120 7290 7416 2742;
1 49 1029 8330 28665 47922 38563 11970;
1 64 1792 19264 90720 219968 287168 191808 51424;
1 81 2916 40068 246078 806274 1509732 1619676 926073 218718;
MAPLE
A289710 := proc(n, r)
if r = 0 then
1;
else
r*binomial(n, r)*binomial(n+r-1, n-1)-n*(r-1)*binomial(n, r) ;
end if ;
end proc:
CROSSREFS
KEYWORD
AUTHOR
R. J. Mathar, Sep 02 2017
STATUS
approved