login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A103684 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),... 15
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; text; internal format)
OFFSET

1,4

LINKS

G. C. Greubel, Table of n, a(n) for the first 8 rows, flattened

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], ...

MATHEMATICA

NestList[ Flatten[ Join[ #, # /. {1 -> {1, 2}, 2 -> {1, 3}, 3->{1}}]] &, {1}, 4] // Flatten (* Robert G. Wilson v, Jul 09 2006 - corrected by G. C. Greubel, Oct 26 2017 *)

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 */

CROSSREFS

Cf. A073058, A103685, A103682.

Sequence in context: A029440 A061337 A253051 * A105103 A086669 A053574

Adjacent sequences:  A103681 A103682 A103683 * A103685 A103686 A103687

KEYWORD

nonn,tabf

AUTHOR

Roger L. Bagula, Mar 26 2005

EXTENSIONS

Image of {3} in the definition corrected by R. J. Mathar, Nov 18 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 07:51 EDT 2019. Contains 322381 sequences. (Running on oeis4.)