Triangle T(n,t) read by rows: the number of n X n {0,1} matrices with trace t where each row sum and each column sum is 4.
A284991
Triangle T(n,t) read by rows: the number of n X n {0,1} matrices with trace t where each row sum and each column sum is 4.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =0a(10) =0a(11) =0a(12) =0a(13) =0a(14) =1a(15) =1a(16) =0a(17) =10a(18) =20a(19) =45a(20) =44a(21) =265a(22) =1920a(23) =6300a(24) =13720a(25) =20175a(26) =18000a(27) =7570a(28) =357435a(29) =2398900
External references
- oeis: A284991