A275869 Number of nonequivalent ways to place k>=0 nonattacking kings on an n X n board.

2, 2, 11, 51, 922, 25618, 1597350, 169413040, 33716225195, 11838480390673, 7588965091313449, 8705702554970941096, 18079208010076976255573, 67519585404524909086260614, 455193583190737164106702088892, 5527752160260327852724215089473548

Offset: 1

Author

Heinrich Ludwig, Dec 11 2016

Keywords

• nonn

Comments

Also number of nonequivalent ways to tile an n+1 X n+1 square with 1 X 1 and 2 X 2 tiles.

Also row sum of triangle A236679.

Rotations and reflections of a placement are not counted. If they are to be counted, see A063443.

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..30

Crossrefs

Cf. A236679, A063443.

Extensions

a(10)-a(16) from Andrew Howroyd, May 30 2017