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%I #17 Jan 10 2021 02:17:56
%S 2,11,12,3,4,1,8,9,10,27,28,29,30,13,14,15,16,5,6,7,22,23,24,25,26,51,
%T 52,53,54,55,56,31,32,33,34,35,36,17,18,19,20,21,44,45,46,47,48,49,50,
%U 83,84,85,86,87,88,89,90,57,58,59,60,61,62,63,64,37,38,39,40,41,42,43
%N Neighbor in 1-2 direction of numbers arranged as clockwise spiral.
%H Peter Kagey, <a href="/A068225/b068225.txt">Table of n, a(n) for n = 1..10000</a>
%H Frank Ellermann, <a href="/A068225/a068225.html">Some EIS sequences based on a spiral of natural numbers</a>.
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>.
%e For example, if the spiral is oriented such that 1 is immediately to the right of 2, as shown below, then a(2) = 11 because 11 is immediately to the right of 2.
%e 21--22--23--24--25--26
%e | |
%e 20 7---8---9---10 27
%e | | | |
%e 19 6 1---2 11 28
%e | | | | |
%e 18 5---4---3 12 29
%e | | |
%e 17--16--15--14--13 30
%e |
%e 36--35--34--33--32--31
%Y Cf. A068226 (inverse, left), A334751 (above), A334752 (below).
%Y Cf. A054552 (middle row right), A054567 (middle row left).
%K nonn,easy
%O 1,1
%A _Frank Ellermann_, Feb 22 2002
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