OFFSET
0,2
PROG
(PARI) {a(n)=sum(k=0, n, k!*abs((matrix(n+1, n+1, r, c, if(r>=c, (r-c)!* sum(m=0, r-c+1, (-1)^(r-c+1-m)*m^r/m!/(r-c+1-m)!)))^-1)[n+1, k+1]))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, May 01 2005
STATUS
approved