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 A352661 #28 Mar 29 2022 05:46:17 %S A352661 0,0,0,0,0,0,0,0,0,0,0,2,2,0,0,12,17,0,0,60,82 %N A352661 Number of doubly symmetric characteristic solutions to the n-superqueens problem. %C A352661 Superqueens are also called amazons. They combine the moves of queen and knight. %D A352661 Martin Gardner, Fractal Music, Hypercards, and More, W H Freeman, 1991, page 238 (based on his column in Scientific American, June 1979). %D A352661 D. E. Knuth, The Art of Computer Programming, Section 7.2.2.3 (draft, March 2022). %e A352661 For n=12 the a(12)=2 solutions are %e A352661 +-------------------------+ +-------------------------+ %e A352661 | . . . . A . . . . . . . | | . . . . A . . . . . . . | %e A352661 | . . . . . . . . . A . . | | . . . . . . . . . A . . | %e A352661 | . A . . . . . . . . . . | | . A . . . . . . . . . . | %e A352661 | . . . . . A . . . . . . | | . . . . . . A . . . . . | %e A352661 | . . . . . . . . . . . A | | . . . . . . . . . . . A | %e A352661 | . . . . . . . . A . . . | | . . . A . . . . . . . . | %e A352661 | . . . A . . . . . . . . | | . . . . . . . . A . . . | %e A352661 | A . . . . . . . . . . . | | A . . . . . . . . . . . | %e A352661 | . . . . . . A . . . . . | | . . . . . A . . . . . . | %e A352661 | . . . . . . . . . . A . | | . . . . . . . . . . A . | %e A352661 | . . A . . . . . . . . . | | . . A . . . . . . . . . | %e A352661 | . . . . . . . A . . . . | | . . . . . . . A . . . . | %e A352661 +-------------------------+ +-------------------------+ %Y A352661 A051224 = A352661 + A352662 + A352663. %Y A352661 A051223 = 2*A352661 + 4*A352662 + 8*A352663 (when n>1). %K A352661 nonn,more %O A352661 1,12 %A A352661 _Don Knuth_, Mar 25 2022