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 A323141 #16 Oct 22 2024 07:59:41 %S A323141 0,0,0,0,2,19,150,1043,6843,43192,266529,1619983,9746883,58220994, %T A323141 345919915 %N A323141 Number of self-trapped uncrossed king's paths on an infinite board after n steps, reduced for symmetry. %C A323141 The average number of moves of a self-avoiding uncrossed random walk of a king on an infinite chessboard to self-trapping is 69.865+-0.008. - _Hugo Pfoertner_, Oct 22 2024 %H A323141 Hugo Pfoertner, <a href="/A323141/a323141.pdf">Probability density for the number of moves to self-trapping</a>, (2019). %e A323141 a(5) = 2: There are 2 walks where the king is blocked after 5 steps, because for the diagonal moves it would have to cross its previous path. %e A323141 . %e A323141 o 2 o o 3 o %e A323141 / \ / \ %e A323141 / \ / \ %e A323141 / \ / \ %e A323141 3 5 1 4 - - - 5 2 %e A323141 | / / / %e A323141 | / / / %e A323141 | / / / %e A323141 4 S o S - - - 1 o %Y A323141 Cf. A003192, A077482, A272773, A323140, A323562. %K A323141 nonn,walk,hard,more %O A323141 1,5 %A A323141 _Hugo Pfoertner_, Jan 05 2019