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%I #8 Jan 23 2019 02:57:23
%S 21,22,24,25,48,49,51,52,57,58,60,61,102,103,105,106,129,130,132,133,
%T 138,139,141,142,165,166,168,169,264,265,267,268,291,292,294,295,300,
%U 301,303,304,345,346,348,349,372,373,375,376,381,382,384,385,408,409,411,412,489,490,492,493,750,751,753,754,777,778,780
%N The fourth greedy 3-free sequence on nonnegative integers.
%C Consider the lexicographically earliest sequence of nonnegative integers that does not contain the arithmetic mean of any pair of terms (such sequences are called 3-free sequences as they do not contain 3-term arithmetic progressions): 0,1,3,4 and so on. This sequence is Stanley sequence S(0,1). Remove numbers in the Stanley sequence from nonnegative integers and repeat the process of finding the next earliest 3-free sequence, which is sequence A323398. The next iteration produces sequence A323418. The fourth iteration produces this sequence.
%C When represented in ternary this sequence consists of integers ending in 10, 11, 20 or 21, and there is exactly one digit 2 before that that might be followed by zeros.
%Y Cf. A005836, A074940, A323398, A323418.
%K nonn
%O 1,1
%A _Tanya Khovanova_ and PRIMES STEP Junior, Jan 14 2019
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