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 A316325 #9 May 07 2019 23:13:49 %S A316325 1,3,6,10,12,15,17,20,24,26,29,32,34,37,41,43,46,50,52,55,58,60,63,67, %T A316325 69,72,74,77,81,83,86,89,91,94,98,100,103,105,108,112,114,117,120,122, %U A316325 125,129,131,134,138,140,143,146,148,151,155,157,160,162,165 %N A316325 Indices of 2's in A305389. %H A316325 Robert Israel, <a href="/A316325/b316325.txt">Table of n, a(n) for n = 1..10000</a> %p A316325 f:= 'f': %p A316325 f(1):= 2: f(2):= 3: f(3):= (1,2,3): %p A316325 S:= [1]; %p A316325 for i from 1 to 5 do T:= map(f,S); U:= map(f,T); S:= map(f,U); od: %p A316325 select(t -> S[t+1]=2, [$0..nops(S)-1]); # _Robert Israel_, May 07 2019 %Y A316325 Cf. A305389. %Y A316325 A316324, A316325, A316326 have the same relation to A305389 as A003144, A003145, A003146 do to the ternary tribonacci word A080843 (or A092782). %K A316325 nonn %O A316325 1,2 %A A316325 _N. J. A. Sloane_, Jul 09 2018