Number of ways of placing n nonattacking queens on n X n board (symmetric solutions count only once).

A002562

Number of ways of placing n nonattacking queens on n X n board (symmetric solutions count only once).

Terms

    a(0) =1a(1) =0a(2) =0a(3) =1a(4) =2a(5) =1a(6) =6a(7) =12a(8) =46a(9) =92a(10) =341a(11) =1787a(12) =9233a(13) =45752a(14) =285053a(15) =1846955a(16) =11977939a(17) =83263591a(18) =621012754a(19) =4878666808a(20) =39333324973a(21) =336376244042

External references