A287407 Start with 0 and repeatedly substitute 0->012, 1->210, 2->201.

0, 1, 2, 2, 1, 0, 2, 0, 1, 2, 0, 1, 2, 1, 0, 0, 1, 2, 2, 0, 1, 0, 1, 2, 2, 1, 0, 2, 0, 1, 0, 1, 2, 2, 1, 0, 2, 0, 1, 2, 1, 0, 0, 1, 2, 0, 1, 2, 2, 1, 0, 2, 0, 1, 2, 0, 1, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 2, 0, 1, 2, 0, 1, 2, 1, 0, 0, 1, 2, 2, 0, 1, 0, 1

Offset: 1

Author

Clark Kimberling, May 25 2017

Keywords

• nonn
• easy

Comments

This is the fixed point of the morphism 0->012, 1->210, 2->201 starting with 0. Let u be the (nonperiodic) sequence of positions of 0, and likewise, v for 1 and w for 2; then u(n)/n -> 3, v(n)/n -> 3, w(n)/n -> 3.

See A287385 for a guide to related sequences.

Examples

			First three iterations of the morphism:  012, 012210201, 012210201201210012201012210.
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..10000
• Index entries for sequences that are fixed points of mappings

Crossrefs

Cf. A287385, A287408, A287409, A287410.

Programs

Mathematica

s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 1, 0}, 2->{2, 0, 1}}] &, {0}, 9]; (*A287407*)
Flatten[Position[s, 0]]; (*A287408*)
Flatten[Position[s, 1]]; (*A287409*)
Flatten[Position[s, 2]]; (*A287410*)
SubstitutionSystem[{0->{0,1,2},1->{2,1,0},2->{2,0,1}},0,{5}][[1]] (* Harvey P. Dale, Aug 03 2023 *)