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 A001440 #11 Feb 01 2022 23:57:07 %S A001440 1,1,1,1,2,5,10,9,10,14,18,17,25,23,31,20,19,10,6,4,8,5,10,0,2,2,7,0, %T A001440 5,4,0,0 %N A001440 Number of symmetric Costas arrays of order n that are inequivalent under dihedral group. %D A001440 CRC Handbook of Combinatorial Designs, C. Colbourn and J. Dinitz, Editors, 1996, IV.7: Costas Arrays by Herbert Taylor (IV.7.6, page 259, Table 2.29). %Y A001440 Cf. A008404, A001441, A001442. %K A001440 nonn,hard,more %O A001440 1,5 %A A001440 _N. J. A. Sloane_