%I #23 Sep 01 2020 13:36:10
%S 1,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,
%T 0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,
%U 1,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,1,0
%N Indicator function of (A003146 prefixed with 0).
%C Also, this has 1's where A275925 has 3's (which is why the offset is 0).
%C Also, apart from the initial 1, this has 1's where the tribonacci word A080843 has 2's.
%C a(n+1) = 1 iff n is a member of A278041, for n >= 0. - _Wolfdieter Lang_, Dec 06 2018
%H N. J. A. Sloane, <a href="/A276791/b276791.txt">Table of n, a(n) for n = 0..10000</a>
%H Wolfdieter Lang, <a href="https://arxiv.org/abs/1810.09787">The Tribonacci and ABC Representations of Numbers are Equivalent</a>, arXiv preprint arXiv:1810.09787 [math.NT], 2018.
%F a(n+1) = t(n)*(t(n) - 1)/2, for n >= 0, and a(0) = 0, where t(n) = A080843(n). - _Wolfdieter Lang_, Dec 06 2018
%Y Cf. A003146, A080843, A275925, A278041.
%Y A276793(n)+A276794(n)+A276791(n)=1; A276796(n)+A276797(n)+A276798(n)=n+1.
%K nonn,easy
%O 0
%A _N. J. A. Sloane_, Oct 18 2016
%E More precise definition by _Georg Fischer_, Sep 01 2020