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 A375762 #16 Aug 29 2024 01:19:29 %S A375762 1,4,8,14,20,30,41,55 %N A375762 Maximum number of knights within an n X n chessboard, where each knight has a path to an edge. %C A375762 Each knight must be either already on an edge square, or have a path of unoccupied squares which reach an unoccupied edge square (and without any other knights moving). %e A375762 For n=3, the following board, with X for each knight, is the unique solution a(3) = 8 and which cannot be 9 since the central square has no move to anywhere within the board. %e A375762 XXX %e A375762 X-X %e A375762 XXX %e A375762 For n=4, the following is a solution for a(4) = 14, with each of the 4 central knights able to make a single move to one of the unoccupied corner squares. %e A375762 -XX- %e A375762 XXXX %e A375762 XXXX %e A375762 XXXX %e A375762 For n = 8, one 55 knight solution is: %e A375762 XXXXXXXX %e A375762 XXXXXXXX %e A375762 XX-X-XXX %e A375762 XX-X-XXX %e A375762 -XX---XX %e A375762 XXXX-XXX %e A375762 XXXXXXXX %e A375762 XXXXXXXX %Y A375762 Cf. A335445 (rooks), A337746 (bishops), A337722 (knights moving off the board). %K A375762 nonn,hard,more %O A375762 1,2 %A A375762 _Walter Robinson_, Aug 26 2024