A350041 Number of ways of placing maximum number of nonattacking rooks on a triangular board with edge-length n (symmetric solutions count only once).

1, 1, 1, 1, 5, 3, 1, 45, 29, 6, 807, 422, 46, 20022, 8270, 424, 642162, 211848

Offset: 1

Author

Alain Brobecker, Dec 10 2021

Keywords

• nonn
• more
• hard

Comments

The rooks placements are considered different when they cannot be obtained by a rotation and/or reflection of another solution that leaves the board inchanged. - Alain Brobecker, Dec 19 2021

a(n) = A350191(n) for n <> 10,13,16,19,... - Vaclav Kotesovec, Dec 20 2021

Links

• Alain Brobecker, Non Attacking Rooks on Hexhex and Triangular boards

Crossrefs

Cf. A004396, A289893, A350191.

Extensions

a(17)-a(18) from Vaclav Kotesovec, Dec 19 2021