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 A188151 #14 Apr 27 2018 09:22:33 %S A188151 0,0,128,800,2112,4008,6472,9504,13104,17272,22008,27312,33184,39624, %T A188151 46632,54208,62352,71064,80344,90192,100608,111592,123144,135264, %U A188151 147952,161208,175032,189424,204384,219912,236008,252672,269904,287704,306072 %N A188151 Number of 6-step self-avoiding walks on an n X n square summed over all starting positions. %C A188151 Row 6 of A188147. %H A188151 R. H. Hardin, <a href="/A188151/b188151.txt">Table of n, a(n) for n = 1..50</a> %F A188151 Empirical: a(n) = 284*n^2 - 1228*n + 1152 for n>4. %F A188151 Conjectures from _Colin Barker_, Apr 27 2018: (Start) %F A188151 G.f.: 8*x^3*(16 + 52*x + 12*x^2 - 7*x^3 - 2*x^4) / (1 - x)^3. %F A188151 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>7. %F A188151 (End) %e A188151 Some solutions for 3 X 3: %e A188151 5 4 3 0 6 7 2 3 4 6 7 0 0 7 0 7 4 3 1 0 0 %e A188151 6 0 2 4 5 0 1 0 5 5 2 1 1 6 5 6 5 2 2 7 6 %e A188151 7 0 1 3 2 1 0 7 6 4 3 0 2 3 4 0 0 1 3 4 5 %Y A188151 Cf. A188147. %K A188151 nonn %O A188151 1,3 %A A188151 _R. H. Hardin_, Mar 22 2011