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A317952 Trajectory of 1 under repeated application of the morphism 1->121, 2->232, 3->343, 4->414. 1
1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 3, 4, 1, 4, 3, 4, 3, 2, 3, 2, 3, 4, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 2, 3, 2, 3, 4, 3, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

Julien Cassaigne, Juhani Karhumäki, Svetlana Puzynina, On k-abelian palindromes, Information and Computation, Volume 260, June 2018, Pages 89-98. See Lemma 1.

FORMULA

From Robert Israel, Aug 20 2018: (Start)

a(3*k) = a(3*k+2) = a(k).

a(3*k+1) == 1 + a(k) mod 4. (End)

MAPLE

A:= [1]:

for k from 1 to 5 do A:= subs([1=(1, 2, 1), 2=(2, 3, 2), 3=(3, 4, 3), 4=(4, 1, 4)], A);

od:

op(A); # Robert Israel, Aug 20 2018

MATHEMATICA

SubstitutionSystem[{1 -> {1, 2, 1}, 2 -> {2, 3, 2}, 3 -> {3, 4, 3}, 4 -> {4, 1, 4}}, 1, 5] // Last (* Jean-François Alcover, Apr 06 2020 *)

CROSSREFS

Sequence in context: A286281 A229830 A105203 * A059131 A059129 A081771

Adjacent sequences:  A317949 A317950 A317951 * A317953 A317954 A317955

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 20 2018

STATUS

approved

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Last modified July 4 16:24 EDT 2020. Contains 335448 sequences. (Running on oeis4.)