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Squares visited on a board numbered in counterclockwise square spiral by successively turning to the left square if it is unvisited or to the right square otherwise.
3

%I #29 Feb 22 2021 13:28:52

%S 1,2,3,4,15,16,5,18,19,6,7,8,23,24,9,10,11,28,29,12,13,14,33,34,61,62,

%T 35,36,17,38,39,68,69,40,41,20,21,22,45,46,77,78,47,48,25,26,27,52,53,

%U 86,87,54,55,30,31,32,59,60,95,96,139,140,97,98,63,64,37

%N Squares visited on a board numbered in counterclockwise square spiral by successively turning to the left square if it is unvisited or to the right square otherwise.

%C The path begins:

%C .

%C ...31

%C |

%C 17 16--15 14--13 30

%C | | |

%C 18---5 4---3 12--29

%C | | |

%C 19---6 1---2 11--28

%C | |

%C 20 7---8 9--10 27

%C | |

%C 21 22 23--24 25 26

%C .

%C This infinite sequence visits every number on the board sooner or later.

%H Kevin Ryde, <a href="/A334619/b334619.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%Y Cf. A316667.

%K nonn

%O 1,2

%A _Mohammed Yaseen_, Sep 09 2020