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%I #17 May 24 2022 02:49:37
%S 1,10,11,13,14,20,22,23,28,37,38,40,41,47,49,50,82,91,92,94,95,101,
%T 103,104,109,118,119,121,122,128,130,131,244,253,254,256,257,263,265,
%U 266,271,280,281,283,284,290,292,293,325,334,335,337,338,344,346,347
%N Sequence contains no 3-term arithmetic progression, starting with 1, 10.
%C a(1)=1, a(2)=10; a(n) is least k such that no three terms of a(1), a(2), ..., a(n-1), k form an arithmetic progression.
%H <a href="/index/No#non_averaging">Index entries related to non-averaging sequences</a>
%F a(n) = (Sum_{k=1..n-1} (3^A007814(k) + 1)/2) + f(n), with f(n) an 8-periodic function with values {1, 9, 8, 9, 5, 10, 10, 10, ...}, n >= 1, as proved by Lawrence Sze.
%Y Cf. A004793, A033157, A093678, A093680, A093681, A092482.
%Y Row 4 of array in A093682.
%K nonn
%O 1,2
%A _Ralf Stephan_, Apr 09 2004
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