A260189 a(n) = A033148(n) / 2^floor(n/4).

1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 4, 8, 0, 0, 15, 22, 0, 0, 52, 51, 0, 0, 257, 342, 0, 0, 1589, 2609, 0, 0, 11417, 16896, 0, 0, 75375, 99114, 0, 0, 616010, 876579, 0, 0, 5253278, 8551800, 0, 0, 49667373, 79595269, 0, 0, 525731268, 764804085, 0, 0, 5932910966, 8905825760, 0, 0

Offset: 1

Author

Vaclav Kotesovec, following a suggestion of Don Knuth, Jul 18 2015

Keywords

• nonn
• hard

References

• W. Ahrens, Mathematische Unterhaltungen und Spiele, 2nd edition, volume 1, Teubner, 1910, pages 249-258.
• Maurice Kraitchik, Le probleme des reines, Bruxelles: L'Échiquier, 1926, 18.

Links

• P. Capstick and K. McCann, The problem of the n queens, apparently unpublished, no date (circa 1990?) [Scanned copy]

Crossrefs

Cf. A002562, A032522, A033148, A037223, A037224.