176041978domain: NAppears in sequencesNumber of n X n 0..1 matrices with row and column i=1..n having sum <= i.at n=5A213955T(n,k)=Number of n X n 0..k matrices with row and column i=1..n having sum <= i*k.at n=20A213962Number of 6X6 0..n matrices with row and column 1..6 having sum <= i*n.at n=0A213966