OFFSET
0,5
LINKS
A. Umar, Combinatorial Results for Semigroups of Orientation-Preserving Partial Transformations, J. Int. Seq. 14 (2011) # 11.7.5, Corollary 10, Table 2.2
EXAMPLE
1 ;
1 1 ;
1 6 2 ;
1 21 36 3 ;
1 60 288 96 4;
1 155 1600 1200 200 5;
1 378 7200 9600 3600 360 6;
1 889 28224 58800 39200 8820 588 7;
1 2040 100352 301056 313600 125440 18816 896 8 ;
1 4599 331776 1354752 2032128 1270080 338688 36288 1296 9;
1 10230 1036800 5529600 11289600 10160640 4233600 806400 64800 1800 10 ;
MAPLE
A289711 := proc(n, p)
if p = 0 then
1;
elif p = 1 then
n*(2^n-1) ;
else
p*2^(n-p)*binomial(n, p)^2 ;
end if ;
end proc:
CROSSREFS
KEYWORD
AUTHOR
R. J. Mathar, Sep 02 2017
STATUS
approved