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 A261597 #17 Sep 16 2015 03:49:02 %S A261597 0,0,0,0,0,0,0,0,0,0,1,3,5,2,4,0,0,0,0,0,0,1,3,5,7,2,4,6,1,5,8,6,3,7, %T A261597 2,4,1,3,6,8,2,4,9,7,5,1,3,6,8,10,5,9,2,4,7,1,3,5,7,9,11,2,4,6,8,10,1, %U A261597 3,5,8,10,12,6,11,2,7,9,4 %N A261597 Triangular array T(n, k) read by rows (n >= 1, 1 <= k <= n): row n gives the lexicographically earliest asymmetric characteristic solution to the n queens problem, or n zeros if no asymmetric characteristic solution exists. The k-th queen is placed in square (k, T(n, k)). %C A261597 See the comments under A260320. %D A261597 Maurice Kraitchik: Mathematical Recreations. Mineola, NY: Dover, 2nd ed. 1953, p. 247-255 (The Problem of the Queens). %e A261597 1 <= n < 5: no ordinary solutions exist. %e A261597 n = 5: 13524 is the first and only solution. %e A261597 *.... %e A261597 ..*.. %e A261597 ....* %e A261597 .*... %e A261597 ...*. %e A261597 n = 6: no ordinary solution exists. %e A261597 n = 7: 1357246 is the first of four existing solutions. %e A261597 n = 8: 15863724 is the first of eleven existing solutions. %e A261597 Triangle starts: %e A261597 0; %e A261597 0, 0; %e A261597 0, 0, 0; %e A261597 0, 0, 0, 0; %e A261597 1, 3, 5, 2, 4; %e A261597 0, 0, 0, 0, 0, 0; %e A261597 1, 3, 5, 7, 2, 4, 6; %e A261597 1, 5, 8, 6, 3, 7, 2, 4; %e A261597 ... %Y A261597 Cf. A141843, A260320, A261595, A261596. %K A261597 nonn,tabl %O A261597 1,12 %A A261597 _Martin Renner_, Aug 25 2015