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%I #31 Feb 12 2024 08:38:27
%S 0,0,1,0,2,0,4,0,4,4,9,0,10,0,10,4,18,0,16,0,20,0,20,4,20,16,29,0,26,
%T 0,34,0,34,4,26,20,41,0,40,0,40,4,34,72,0,45,0,41,61,0,74,0,58,0,50,0,
%U 61,50,5,0,58,32,0,85,0,113,0,89,0,73,0,89,16,53,0,85,68,0,89,61,65,0,145,0
%N a(0) = 0; for n > 0, a(n) is the largest distance squared on a square spiral between a(n-1) and any previous occurrence of a(n-1). If a(n-1) has not previously occurred then a(n) = 0.
%H Scott R. Shannon, <a href="/A365344/b365344.txt">Table of n, a(n) for n = 0..10000</a>
%e The spiral begins:
%e .
%e 41--20--26--4---34--0---34 .
%e | | .
%e 0 18--4---10--0---10 0 50
%e | | | | |
%e 40 0 2---0---1 0 26 0
%e | | | | | | |
%e 0 16 0 0---0 9 0 58
%e | | | | | |
%e 40 0 4---0---4---4 29 0
%e | | | |
%e 4 20--0---20--4---20--16 74
%e | |
%e 34--72--0---45--0---41--61--0
%e .
%e .
%e a(4) = 2 as a(3) = 0 and the largest square distance between a(3) and a previous occurrence of 0 is 2 - between a(3) and a(1).
%e a(47) = 41 as a(46) = 0 and the largest square distance between a(46) and a previous occurrence of 0 is 41 - between a(46) and a(37). This is the first term to differ from A365343.
%Y Cf. A366543, A366353, A366354, A001481.
%K nonn
%O 0,5
%A _Scott R. Shannon_, Oct 16 2023