Number of arrangements of rooks with rotational symmetry on a triangular grid with n grid points on each side and no two rooks on the same row, column or diagonal.
A326611
Number of arrangements of rooks with rotational symmetry on a triangular grid with n grid points on each side and no two rooks on the same row, column or diagonal.
Terms
- a(0) =2a(1) =1a(2) =1a(3) =4a(4) =3a(5) =5a(6) =10a(7) =9a(8) =15a(9) =40a(10) =41a(11) =65a(12) =162a(13) =189a(14) =321a(15) =780a(16) =919a(17) =1681a(18) =4034a(19) =5281a(20) =9259a(21) =23936a(22) =30665a(23) =57601a(24) =143602a(25) =199577a(26) =367561a(27) =959236a(28) =1323243a(29) =2585133
External references
- oeis: A326611