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 A374933 #18 Jul 30 2024 17:56:29 %S A374933 9,15,23,30,37,44,52,60,68,76,84,92,100,108,116,124,132,140,148,156, %T A374933 164,172,180,188,196,204,212,220,228,236,244,252,260,268,276,284,292, %U A374933 300,308,316,324,332,340,348,356,364,372,380,388,396,404,412,420 %N A374933 Maximum number of squares covered (i.e., attacked) by 2 independent (i.e., non-attacking) queens on an n X n chessboard. %C A374933 It is not possible to place two non-attacking queens on a 1 X 1 or 2 X 2 chessboard. %H A374933 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A374933 a(n) = 8*n - 20 for n >= 8. %F A374933 G.f.: x^3*(9 - 3*x + 2*x^2 - x^3 + x^6)/(1 - x)^2. - _Stefano Spezia_, Jul 25 2024 %Y A374933 Cf. A017113, A047461 (case for one queen). %K A374933 nonn,easy %O A374933 3,1 %A A374933 _John King_, Jul 24 2024