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%I #10 Aug 07 2019 16:55:17
%S 1,2,3,5,4,7,8,14,6,9,18,10,11,19,12,13,24,15,22,16,28,17,25,21,38,20,
%T 26,54,23,29,60,27,30,59,31,32,61,34,37,67,35,36,68,33,39,77,40,41,76,
%U 42,47,92,43,44,87,45,46,91,48,50,98,49,51,100,53,55,105
%N Lexicographically earliest sequence of distinct positive integers such that for any n > 0, the area of the triangle ((n, a(n)), (n+1, a(n+1)), (n+2, a(n+2))) is unique.
%C For any n > 0, the area of the triangle ((n, a(n)), (n+1, a(n+1)), (n+2, a(n+2))) equals abs(2*a(n+1) - a(n) - a(n+2)).
%C This sequence has similarities with A081145; here the absolute value of the second difference is unique, there the absolute value of the first difference.
%H Rémy Sigrist, <a href="/A326777/b326777.txt">Table of n, a(n) for n = 1..1000</a>
%H Rémy Sigrist, <a href="/A326777/a326777_1.gp.txt">PARI program for A326777</a>
%e The first terms, alongside the area of the n-th triangle, are:
%e n a(n) Area
%e -- ---- ----
%e 1 1 0
%e 2 2 1
%e 3 3 3
%e 4 5 4
%e 5 4 2
%e 6 7 5
%e 7 8 14
%e 8 14 11
%e 9 6 6
%e 10 9 17
%e 11 18 9
%e 12 10 7
%e 13 11 15
%o (PARI) See Links section.
%Y Cf. A081145.
%K nonn
%O 1,2
%A _Rémy Sigrist_, Jul 29 2019
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