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

1,5

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

Table of n, a(n) for n=1..18.

Alain Brobecker, Non Attacking Rooks on Hexhex and Triangular boards

Crossrefs

Cf. A004396, A289893, A350191.

Sequence in context: A143410 A114344 A350191 * A317674 A201333 A353179

Adjacent sequences: A350038 A350039 A350040 * A350042 A350043 A350044

Keyword

nonn,more,hard

Author

Alain Brobecker, Dec 10 2021

Extensions

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

Status

approved