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 A317191 Fill an n X n square array T(j,k), 1<=j<=n, 1=k<=n, by antidiagonals upwards in which each term is the least nonnegative integer satisfying the condition that no row, column, diagonal, or antidiagonal contains a repeated term; a(n) = T(n,n). 0
 0, 3, 5, 4, 1, 10, 7, 2, 6, 8, 15, 12, 19, 17, 22, 23, 12, 26, 11, 31, 32, 12, 35, 10, 37, 42, 40, 45, 33, 49, 18, 17, 20, 53, 16, 51, 59, 18, 59, 60, 58, 64, 69, 69, 38, 29, 74, 26, 68, 78, 80, 36, 30, 33, 41, 39, 32, 33, 92, 41, 38, 89, 32, 35 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This is the analog for an n X n board of the sequence A317190 (which is the main diagonal when we fill in the whole of the fourth quadrant in this way). LINKS F. Michel Dekking, Jeffrey Shallit, and N. J. A. Sloane, Queens in exile: non-attacking queens on infinite chess boards, Electronic J. Combin., 27:1 (2020), #P1.52. EXAMPLE For n=3 the array T is 0 2 1 1 3 4 2 0 5 so a(3) = T(3,3) = 5. For n=6 the array T is 0 2 1 5 3 4 1 3 4 0 7 2 2 0 5 1 6 9 3 1 2 4 0 5 4 6 0 3 1 7 5 7 8 6 4 10 so a(6) = T(6,6) = 10. This is the first time this sequence differs from A317190. CROSSREFS Cf. A317190, A274318, A269529, A274528. Sequence in context: A073006 A320029 A317190 * A165109 A134892 A253074 Adjacent sequences:  A317188 A317189 A317190 * A317192 A317193 A317194 KEYWORD nonn AUTHOR N. J. A. Sloane and Doron Zeilberger, Jul 30 2018 STATUS approved

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Last modified September 18 03:39 EDT 2020. Contains 337164 sequences. (Running on oeis4.)