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 A366331 #18 Dec 12 2023 20:45:34 %S A366331 1,0,1,1,0,2,20,0,272,1208,0,127334,1958084,0 %N A366331 Number of main classes of diagonal Latin squares of order 2n+1 that contain a horizontally semicyclic Latin square. %C A366331 A horizontally semicyclic diagonal Latin square is a square where each row r(i) is a cyclic shift of the first row r(0) by some value d(i) (see example). %H A366331 Eduard I. Vatutin, <a href="https://vk.com/wall162891802_1911">About the horizontally and vertically semicyclic diagonal Latin squares enumeration</a> (in Russian). %H A366331 Eduard I. Vatutin, <a href="https://vk.com/wall162891802_2443">About the spectra of numerical characteristics of different types of cyclic diagonal Latin squares</a> (in Russian). %H A366331 Eduard I. Vatutin, <a href="https://vk.com/wall162891802_2450">About the number of main classes of semicyclic diagonal Latin squares of order 17</a> (in Russian). %H A366331 Eduard I. Vatutin, <a href="https://vk.com/wall162891802_2453">About the number of main classes of semicyclic diagonal Latin squares of order 19</a> (in Russian). %H A366331 Eduard I. Vatutin, <a href="http://evatutin.narod.ru/evatutin_horz_semicyclic_cfs_n5-19.zip">Lists of canonical forms of semicyclic diagonal Latin squares of orders 5-19</a>. %H A366331 <a href="https://oeis.org/index/La#Latin">Index entries for sequences related to Latin squares and rectangles</a>. %e A366331 Example of horizontally semicyclic diagonal Latin square of order 13: %e A366331 0 1 2 3 4 5 6 7 8 9 10 11 12 %e A366331 2 3 4 5 6 7 8 9 10 11 12 0 1 (d=2) %e A366331 4 5 6 7 8 9 10 11 12 0 1 2 3 (d=4) %e A366331 9 10 11 12 0 1 2 3 4 5 6 7 8 (d=9) %e A366331 7 8 9 10 11 12 0 1 2 3 4 5 6 (d=7) %e A366331 12 0 1 2 3 4 5 6 7 8 9 10 11 (d=12) %e A366331 3 4 5 6 7 8 9 10 11 12 0 1 2 (d=3) %e A366331 11 12 0 1 2 3 4 5 6 7 8 9 10 (d=11) %e A366331 6 7 8 9 10 11 12 0 1 2 3 4 5 (d=6) %e A366331 1 2 3 4 5 6 7 8 9 10 11 12 0 (d=1) %e A366331 5 6 7 8 9 10 11 12 0 1 2 3 4 (d=5) %e A366331 10 11 12 0 1 2 3 4 5 6 7 8 9 (d=10) %e A366331 8 9 10 11 12 0 1 2 3 4 5 6 7 (d=8) %Y A366331 Cf. A071607, A123565, A287764, A338562, A342990, A343866. %K A366331 nonn,more,hard %O A366331 0,6 %A A366331 _Eduard I. Vatutin_, Oct 07 2023 %E A366331 a(11)-a(13) from _Andrew Howroyd_, Nov 02 2023