Triangle T(n,k) = number of rational (0,1) matrices of rank k (n >= 0, 0 <= k <= n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =9a(5) =6a(6) =1a(7) =49a(8) =288a(9) =174a(10) =1a(11) =225a(12) =6750a(13) =36000a(14) =22560a(15) =1a(16) =961a(17) =118800a(18) =3159750a(19) =17760600a(20) =12514320a(21) =1a(22) =3969a(23) =1807806a(24) =190071000a(25) =5295204600a(26) =34395777360a(27) =28836612000a(28) =1a(29) =16129