A350585 - OEIS

%I #25 Jan 29 2023 09:43:31

%S 1,0,0,1,1,0,4,25,295

%N a(n) is the number of distinct numbers of transversals that an orthogonal diagonal Latin square of order n can have.

%C An orthogonal diagonal Latin square is a diagonal Latin square with at least one orthogonal diagonal mate. Since all orthogonal diagonal Latin squares are diagonal Latin squares, a(n) <= A344105(n).

%C a(10) >= 193, a(11) >= 3588, a(12) >= 10465. - updated by _Eduard I. Vatutin_, Jan 29 2023

%H Eduard I. Vatutin, <a href="https://vk.com/wall162891802_1709">About the spectra of numerical characteristics of orthogonal diagonal Latin squares of orders 1-11</a> (in Russian).

%H Eduard I. Vatutin, <a href="http://evatutin.narod.ru/spectra/spectra_odls_transversals_all.png">Graphical representation of the spectra</a>.

%H Eduard I. Vatutin, Examples (<a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n1_1_item.txt">1</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n4_1_item.txt">4</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n5_1_item.txt">5</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n7_4_items.txt">7</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n8_25_items.txt">8</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n9_295_items.txt">9</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n10_193_known_items.txt">10</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n11_3588_known_items.txt">11</a>, <a href="http://evatutin.narod.ru/spectra/spectrum_odls_transversals_n12_10465_known_items.txt">12</a>).

%H E. I. Vatutin, N. N. Nikitina, M. O. Manzuk, A. M. Albertyan and I. I. Kurochkin, <a href="http://evatutin.narod.ru/evatutin_spectra_t_dt_i_o_small_orders_thesis.pdf">On the construction of spectra of fast-computable numerical characteristics for diagonal Latin squares of small order</a>,  Intellectual and Information Systems (Intellect - 2021). Tula, 2021. pp. 7-17. (in Russian)

%H <a href="/index/La#Latin">Index entries for sequences related to Latin squares and rectangles</a>.

%e For n=8 the number of transversals that an orthogonal diagonal Latin square of order 8 may have is 16, 32, 40, 48, 52, 56, 60, 64, 68, 72, 76, 80, 88, 96, 112, 128, 132, 144, 160, 168, 192, 224, 256, 320, or 384. Since there are 25 distinct values, a(8)=25.

%Y Cf. A305570, A344105, A349199.

%K nonn,more,hard

%O 1,7

%A _Eduard I. Vatutin_, Mar 27 2022