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 A309221 #7 Aug 28 2019 18:26:13 %S A309221 1,2,23,240,2355,22320,205942,1866592,16664147,147164464,1287061400, %T A309221 11174456704,96362903378,826641224992,7055950608008,59990171328640, %U A309221 508090131646771,4290071141315376,36113651041694280,303253863622924416,2540231448366573400 %N A309221 Expected number of distinct squares visited by a knight's random walk on an infinite chessboard after n steps, normalized to give an integer. %C A309221 Based on A326954/A326955. %C A309221 a(0)=1; for n>0, a(n) = (A326954(n)/A326955(n))*2^(3*n-3). (It is only a conjecture that this is always an integer). %Y A309221 Cf. A326954, A326955. %K A309221 nonn %O A309221 0,2 %A A309221 _N. J. A. Sloane_, Aug 28 2019