a(n) is the number of ways to place non-attacking queens on an n X n board with no queens above the main diagonal.
A359032
a(n) is the number of ways to place non-attacking queens on an n X n board with no queens above the main diagonal.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =9a(4) =23a(5) =66a(6) =204a(7) =669a(8) =2305a(9) =8348a(10) =31542a(11) =124021a(12) =507937a(13) =2154494a(14) =9455972a(15) =42847307a(16) =200258387a(17) =962904904a(18) =4759773172a(19) =24142168317a(20) =125575232141a(21) =668689805690
External references
- oeis: A359032