OFFSET
1,1
COMMENTS
Essentially the same as A026460. [From R. J. Mathar, Oct 23 2008]
LINKS
Christopher R. H. Hanusa, T Zaslavsky, S Chaiken, A q-Queens Problem. IV. Queens, Bishops, Nightriders (and Rooks), arXiv preprint arXiv:1609.00853, a12016
MATHEMATICA
a[1] = 3; a[2] = 4; a[n_] := a[n] =
For[k = a[n-1]+1, True, k++, a[n] = k; If[AllTrue[Tuples[Range[n], {2}], k != a[#[[1]]] a[#[[2]]] - 2&], Return[k]]
];
Array[a, 60] (* Jean-François Alcover, Oct 30 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved