A390736 Number of n X n grids with 3 non-attacking kings on each row.

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 20, 263928, 22868187338, 1034937133971366, 46636257344451763934, 1990740376914748532578610, 84433188888432939678771427334, 3657103798685771128160178096325444, 165258835167767029550384983801808942466

Offset

0,12

Links

Hamidreza Maleki Tirabadi, Table of n, a(n) for n = 0..30

Formula

See A390419.

Example

a(11) = 20. One of the 20 solutions is:
  Row 1:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °
  Row 2:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *
  Row 3:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °
  Row 4:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *
  Row 5:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °
  Row 6:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *
  Row 7:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °
  Row 8:  [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *
  Row 9:  [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °
  Row 10: [6, 8, 10] -> ° ° ° ° ° ° * ° * ° *
  Row 11: [0, 2, 4]  -> * ° * ° * ° ° ° ° ° °

Crossrefs

Column k=3 of A390419.

Cf. A389770, A387098.

Sequence in context: A078354 A203306 A211489 * A172669 A056104 A051117

Adjacent sequences: A390733 A390734 A390735 * A390737 A390738 A390739

Keyword

nonn

Author

Hamidreza Maleki Tirabadi, Nov 16 2025

Status

approved