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%I #8 Aug 22 2019 17:45:11
%S 1,1,1,34,45,76,98,135,181,234,290,338,413,487,566,654,742,823,930,
%T 1051,1169,1291,1414,1548,1685,1813,1968,2138,2304,2455,2632,2815,
%U 3016,3187,3388,3597,3803,4026,4246,4473,4714,4948,5194,5447,5702,5969,6244,6514
%N Last cell visited by knight moves on a spirally numbered hexagonal board of edge-length n, moving to the lowest unvisited cell at each step.
%C A hexagonal board of edge-length 3, for example, is numbered spirally as:
%C .
%C 17--18--19
%C /
%C 16 6---7---8
%C / / \
%C 15 5 1---2 9
%C \ \ / /
%C 14 4---3 10
%C \ /
%C 13--12--11
%C .
%C In Glinski's hexagonal chess, a knight (N) can move to these (o) cells:
%C .
%C . . . . .
%C . . o o . .
%C . o . . . o .
%C . o . . . . o .
%C . . . . N . . . .
%C . o . . . . o .
%C . o . . . o .
%C . . o o . .
%C . . . . .
%C .
%C a(n) stays constant at 72085 for n >= 177 since 72085 is also the last cell visited by knight moves on a spirally numbered infinite hexagonal board, moving to the lowest unvisited cell at each step.
%H Sangeet Paul, <a href="/A327132/b327132.txt">Table of n, a(n) for n = 1..200</a>
%H Chess variants, <a href="https://www.chessvariants.com/hexagonal.dir/hexagonal.html">Glinski's Hexagonal Chess</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Hexagonal_chess#Gli%C5%84ski's_hexagonal_chess">Hexagonal chess - Gliński's hexagonal chess</a>
%Y Cf. A308312, A327131.
%K nonn
%O 1,4
%A _Sangeet Paul_, Aug 22 2019