cp's OEIS Frontend

A020661 Lexicographically earliest increasing sequence of nonnegative numbers that contains no arithmetic progression of length 9.

%I A020661 #17 Oct 01 2019 02:58:40
%S A020661 0,1,2,3,4,5,6,7,9,10,11,12,13,14,15,16,18,19,20,21,22,23,26,27,28,29,
%T A020661 30,31,32,33,36,37,38,39,40,42,43,44,45,46,47,48,49,52,54,55,56,57,58,
%U A020661 59,63,64,65,66,67,68,69,70,77,78,79,80,81,82,83,84,86,87,90,91,93,94,95,96,97
%N A020661 Lexicographically earliest increasing sequence of nonnegative numbers that contains no arithmetic progression of length 9.
%H A020661 David W. Wilson, <a href="/A020661/b020661.txt">Table of n, a(n) for n = 1..10000</a>
%Y A020661 Summary of increasing sequences avoiding arithmetic progressions of specified lengths (the second of each pair is obtained by adding 1 to the first):
%Y A020661 3-term AP: A005836 (>=0), A003278 (>0);
%Y A020661 4-term AP: A005839 (>=0), A005837 (>0);
%Y A020661 5-term AP: A020654 (>=0), A020655 (>0);
%Y A020661 6-term AP: A020656 (>=0), A005838 (>0);
%Y A020661 7-term AP: A020657 (>=0), A020658 (>0);
%Y A020661 8-term AP: A020659 (>=0), A020660 (>0);
%Y A020661 9-term AP: A020661 (>=0), A020662 (>0);
%Y A020661 10-term AP: A020663 (>=0), A020664 (>0).
%K A020661 nonn
%O A020661 1,3
%A A020661 _David W. Wilson_