A194496 Number of ways to arrange 6 nonattacking queens on the lower triangle of an n X n board.

0, 0, 0, 0, 0, 0, 0, 0, 64, 1644, 19306, 146718, 820218, 3670288, 13846830, 45661556, 134896662, 364019248, 909633276, 2129318414, 4709083054, 9912162234, 19970298696, 38707229282, 72458290216, 131476840106, 231906957348

Offset

1,9

Comments

Column 6 of A194498.

Links

R. H. Hardin, Table of n, a(n) for n = 1..35

Example

Some solutions for 9 X 9:
  0                  0                  0                  0
  0 1                0 0                1 0                0 0
  0 0 0              1 0 0              0 0 0              0 1 0
  1 0 0 0            0 0 0 0            0 0 0 0            0 0 0 0
  0 0 0 0 0          0 0 0 0 1          0 0 0 0 1          1 0 0 0 0
  0 0 0 1 0 0        0 0 1 0 0 0        0 1 0 0 0 0        0 0 1 0 0 0
  0 0 0 0 0 1 0      0 0 0 0 0 1 0      0 0 0 1 0 0 0      0 0 0 0 1 0 0
  0 0 1 0 0 0 0 0    0 0 0 1 0 0 0 0    0 0 0 0 0 1 0 0    0 0 0 0 0 0 0 1
  0 0 0 0 1 0 0 0 0  0 1 0 0 0 0 0 0 0  0 0 1 0 0 0 0 0 0  0 0 0 1 0 0 0 0 0

Crossrefs

Sequence in context: A162994 A225981 A232427 * A297092 A284340 A195807

Adjacent sequences: A194493 A194494 A194495 * A194497 A194498 A194499

Keyword

nonn

Author

R. H. Hardin, Aug 26 2011

Status

approved