This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A179040 #13 Sep 14 2022 16:54:54 %S A179040 1,1,2,4,18,56,272,1000,6080,33644,214024,1363836,10877964,75783376, %T A179040 648644300,5765475224,49406530846,431491536076 %N A179040 Number of permutations of 1..n with no three elements collinear. %C A179040 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. %H A179040 Dániel T. Nagy, Zoltán Lóránt Nagy, and Russ Woodroofe, <a href="https://arxiv.org/abs/2209.01447">The extensible No-Three-In-Line problem</a>, arXiv:2209.01447 [math.CO], 2022. %Y A179040 For "collinear modulo n" see A135538 and A146558. %K A179040 nonn %O A179040 0,3 %A A179040 _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 %E A179040 a(0)=1 prepended by _Alois P. Heinz_, Sep 14 2022