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 A342998 #33 May 05 2021 13:59:16 %S A342998 1,0,5,27,0,4523,128818,0,204330233,11232045257 %N A342998 Minimum number of diagonal transversals in a cyclic diagonal Latin square of order 2n+1. %C A342998 A cyclic Latin square is a Latin square in which row i is obtained by cyclically shifting row i-1 by d places (see A338562, A123565 and A341585). %C A342998 Cyclic diagonal Latin squares do not exist for even orders. %C A342998 a(n) <= A342997(n). %C A342998 All cyclic diagonal Latin squares are diagonal Latin squares, so A287647(n) <= a((n-1)/2). %H A342998 Eduard I. Vatutin, <a href="https://vk.com/wall162891802_1412">Enumerating the diagonal transversals for cyclic diagonal Latin squares of orders 1-19</a> (in Russian). %H A342998 Eduard I. Vatutin, <a href="/A342998/a342998.txt">Proving list (best known examples)</a>. %H A342998 <a href="/index/La#Latin">Index entries for sequences related to Latin squares and rectangles</a>. %e A342998 For n=2 one of best cyclic diagonal Latin squares of order 5 %e A342998 0 1 2 3 4 %e A342998 2 3 4 0 1 %e A342998 4 0 1 2 3 %e A342998 1 2 3 4 0 %e A342998 3 4 0 1 2 %e A342998 has a(2)=5 diagonal transversals: %e A342998 0 . . . . . 1 . . . . . 2 . . . . . 3 . . . . . 4 %e A342998 . . 4 . . . . . 0 . . . . . 1 2 . . . . . 3 . . . %e A342998 . . . . 3 4 . . . . . 0 . . . . . 1 . . . . . 2 . %e A342998 . 2 . . . . . 3 . . . . . 4 . . . . . 0 1 . . . . %e A342998 . . . 1 . . . . . 2 3 . . . . . 4 . . . . . 0 . . %Y A342998 Cf. A006717, A123565, A287647, A287648, A338562, A341585, A342997. %K A342998 nonn,more,hard %O A342998 0,3 %A A342998 _Eduard I. Vatutin_, Apr 02 2021