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A103684
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Triangle read by rows, based on the morphism f: 1->{1,2}, 2->{1,3}, 3->{1}. First row is 1. If current row is a,b,c,..., then the next row is a,b,c,...,f(a),f(b),f(c),...
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12
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1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 2, 1, 3, 1, 2, 1, 1, 2, 1, 3, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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EXAMPLE
| [1], [1,1,2], [1,1,2,1,2,1,2,1,3], [1,1,2,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,3,1,2,1,3,1,2,1], ...
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MATHEMATICA
| NestList[ Flatten[ Join[ #, # /. {1 -> {1, 2}, 2 -> {1, 3}}]] &, {1}, 4] // Flatten (from Robert G. Wilson v (rgwv(at)rgwv.com), Jul 09 2006)
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PROG
| (PARI) {a(n)=local(m, v, w); v=w=[1]; while(length(w)<n, m=length(v); for(k=1, m, v=concat(v, [[1, 2], [1, 3], [1]][v[k]])); w=concat(w, v)); w[n]} /* Michael Somos Apr 16 2005 */
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CROSSREFS
| Cf. A073058, A103685, A103682.
Sequence in context: A131406 A029440 A061337 * A105103 A086669 A053574
Adjacent sequences: A103681 A103682 A103683 * A103685 A103686 A103687
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KEYWORD
| nonn,tabf
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AUTHOR
| Roger Bagula (rlbagulatftn(AT)yahoo.com), Mar 26 2005
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EXTENSIONS
| Image of {3} in the definition corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 18 2010
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