A179040 Number of permutations of 1..n with no three elements collinear.

1, 1, 2, 4, 18, 56, 272, 1000, 6080, 33644, 214024, 1363836, 10877964, 75783376, 648644300, 5765475224, 49406530846, 431491536076

Offset: 0

Author

R. H. Hardin, including comments and references from R. J. Mathar, Max Alekseyev and Franklin T. Adams-Watters in the Sequence Fans Mailing List, Jun 25 2010

Keywords

• nonn

Comments

Number of permutations of 1..n with no three points (i,p(i)) (j,p(j)) (k,p(k)) collinear, or number of n X n permutation matrices with no three 1's collinear.

Links

• Dániel T. Nagy, Zoltán Lóránt Nagy, and Russ Woodroofe, The extensible No-Three-In-Line problem, arXiv:2209.01447 [math.CO], 2022.

Crossrefs

For "collinear modulo n" see A135538 and A146558.

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 14 2022