Number of n X n binary matrices with exactly 2 ones in each row and column, and with rows and columns in lexicographically nondecreasing order.
A229161
Number of n X n binary matrices with exactly 2 ones in each row and column, and with rows and columns in lexicographically nondecreasing order.
Terms
- a(0) =0a(1) =1a(2) =1a(3) =2a(4) =5a(5) =13a(6) =42a(7) =155a(8) =636a(9) =2889a(10) =14321a(11) =76834a(12) =443157
External references
- oeis: A229161