%I A003146 M3407
%S A003146 4,11,17,24,28,35,41,48,55,61,68,72,79,85,92,98,105,109,116,122,129,136,
%T A003146 142,149,153,160,166,173,177,184,190,197,204,210,217,221,228,234,241,247,
%U A003146 254,258,265,271,278,285,291,298,302,309,315,322,329,335,342,346,353,359
%N A003146 A self-generating sequence.
%C A003146 Comment from Philippe DELEHAM: A003144, A003145, A003146 may be defined 
               as follows. Consider the maps a -> ab, b ->ac, c ->a, starting from 
               a(1) = a; then A003144 gives the indices of a, A003145 gives the 
               indices of b and A003146 gives the indices of c. The sequence of 
               letters in the infinite word begins a, b, a, c, a, b, a, a, b, a, 
               c, a, b, a, b, a, c, ... Setting a = 1, b = 2, c = 3 gives A092782.
%C A003146 Also, indices of c in the sequence closed under a -> abac, b -> aba, 
               c -> ab; starting with a(1) = a. - DELEHAM Philippe (kolotoko(AT)wanadoo.fr), 
               Apr 16 2004
%D A003146 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A003146 L. Belanger and S. Brlek, On tribonacci sequences, preprint, 1998.
%D A003146 L. Carlitz, R. Scoville and V. E. Hoggatt, Jr., Fibonacci representations 
               of higher order, Fib. Quart., 10 (1972), 43-69.
%H A003146 N. J. A. Sloane, <a href="b003146.txt">Table of n, a(n) for n = 1..3136</
               a>
%p A003146 M:=17; S[1]:=`a`; S[2]:=`ab`; S[3]:=`abac`;
%p A003146 for n from 4 to M do S[n]:=cat(S[n-1], S[n-2], S[n-3]); od:
%p A003146 t0:=S[M]: l:=length(t0); t1:=[];
%p A003146 for i from 1 to l do if substring(t0,i..i) = `c` then t1:=[op(t1),i]; 
               fi; od: (N. J. A. Sloane, Nov 01 2006)
%Y A003146 Cf. A003145, A003144, A080843, A092782.
%Y A003146 Sequence in context: A107988 A038241 A160907 this_sequence A063237 A026381 
               A063556
%Y A003146 Adjacent sequences: A003143 A003144 A003145 this_sequence A003147 A003148 
               A003149
%K A003146 nonn
%O A003146 1,1
%A A003146 N. J. A. Sloane (njas(AT)research.att.com).
%E A003146 More terms from DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Apr 16 2004