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%I #7 Feb 04 2022 14:40:42
%S 1,0,2,8,40,1380,211164,205331148
%N Number of simple paths for a Racetrack car (using von Neumann neighborhood) with initial velocity zero, going from one corner to the diagonally opposite corner on an n X n grid.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Racetrack_(game)">Racetrack</a>
%e For n = 4 the following paths, together with their reflections in the diagonal, exist. The numbers give the positions of the car after successive steps. In total, there are a(4) = 2*4 = 8 possible paths.
%e ...3 ...4 ...4 ...5
%e .... ...3 ..3. ...4
%e ..2. ..2. ..2. ...3
%e 01.. 01.. 01.. 012.
%Y Main diagonal of A351108.
%Y Cf. A007764, A351042, A351107.
%K nonn,more
%O 1,3
%A _Pontus von Brömssen_, Feb 01 2022
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