This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A316326 #9 May 07 2019 23:13:56 %S A316326 2,4,7,8,11,13,16,18,21,22,25,27,30,33,35,38,39,42,44,47,48,51,53,56, %T A316326 59,61,64,65,68,70,73,75,78,79,82,84,87,90,92,95,96,99,101,104,106, %U A316326 109,110,113,115,118,121,123,126,127,130,132,135,136,139,141,144,147,149,152,153,156,158,161,163,166,167,170,172 %N A316326 Indices of 3's in A305389. %H A316326 Robert Israel, <a href="/A316326/b316326.txt">Table of n, a(n) for n = 1..10000</a> %p A316326 f:= 'f': %p A316326 f(1):= 2: f(2):= 3: f(3):= (1,2,3): %p A316326 S:= [1]; %p A316326 for i from 1 to 5 do T:= map(f,S); U:= map(f,T); S:= map(f,U); od: %p A316326 select(t -> S[t+1]=3, [$0..nops(S)-1]); # _Robert Israel_, May 07 2019 %Y A316326 Cf. A305389. %Y A316326 A316324, A316325, A316326 have the same relation to A305389 as A003144, A003145, A003146 do to the ternary tribonacci word A080843 (or A092782). %K A316326 nonn %O A316326 1,1 %A A316326 _N. J. A. Sloane_, Jul 09 2018