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 A140518 #18 Mar 31 2023 15:31:27 %S A140518 1,5,235,96371,447544629,22132498074021,10621309947362277575, %T A140518 50819542770311581606906543,2460791237088492025876789478191411, %U A140518 1207644919895971862319430895789323709778193,5996262208084349429209429097224046573095272337986011 %N A140518 Number of simple paths from corner to corner of an n X n grid with king-moves allowed. %C A140518 This graph is the "strong product" of P_n with P_n, where P_n is a path of length n. Sequence A007764 is what we get when we restrict ourselves to rook moves of unit length. %C A140518 Computed using ZDDs (ZDD = "reduced, order, zero-suppressed binary decision diagram"). %D A140518 Donald E. Knuth, The Art of Computer Programming, Vol. 4, fascicle 1, section 7.1.4, p. 117, Addison-Wesley, 2009. %H A140518 Jens Weise, <a href="https://opendata.uni-halle.de/bitstream/1981185920/103345/1/Weise_Jens_Dissertation_2023.pdf">Evolutionary Many-Objective Optimisation for Pathfinding Problems</a>, Ph. D. Dissertation, Otto von Guercke Univ., Magdeburg (Germany, 2022), see p. 53. %e A140518 For example, when n=8 this is the number of ways to move a king from a1 to h8 without occupying any cell twice. %Y A140518 Main diagonal of A329118. %Y A140518 Cf. A140519, A158651, A234622, A007764, A038496. %Y A140518 Cf. A220638 (Hosoya index). %K A140518 nonn,walk %O A140518 1,2 %A A140518 _Don Knuth_, Jul 26 2008 %E A140518 a(9)-a(11) from _Andrew Howroyd_, Apr 07 2016