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 A320575 #12 Oct 22 2018 01:38:54 %S A320575 1,2,6,2,2,28,2,4,2,8,4,2,2,4 %N A320575 a(n) gives the number of configurations of n non-attacking rooks on an n X n chessboard such that the number of distinct distances between the rooks is given by A319476(n). %e A320575 For n = 7 the a(7) = 2 boards are mirror images of each other: %e A320575 +---+---+---+---+---+---+---+ %e A320575 7 | | | * | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 6 | | | | | | * | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 5 | * | | | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 4 | | | | * | | | | %e A320575 +---+---+---+---+---+---+---+. %e A320575 3 | | | | | | | * | %e A320575 +---+---+---+---+---+---+---+ %e A320575 2 | | * | | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 1 | | | | | * | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 A B C D E F G %e A320575 +---+---+---+---+---+---+---+ %e A320575 7 | | | | | * | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 6 | | * | | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 5 | | | | | | | * | %e A320575 +---+---+---+---+---+---+---+ %e A320575 4 | | | | * | | | | %e A320575 +---+---+---+---+---+---+---+. %e A320575 3 | * | | | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 2 | | | | | | * | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 1 | | | * | | | | | %e A320575 +---+---+---+---+---+---+---+ %e A320575 A B C D E F G %Y A320575 Cf. A319476, A320575, A320576, A320448, A320573, A320574. %K A320575 nonn,more %O A320575 1,2 %A A320575 _Peter Kagey_, Oct 15 2018 %E A320575 a(10) corrected and a(11)-a(14) from _Giovanni Resta_, Oct 21 2018