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A253091 List of ternary words obtained by expanding (1+2x)^n mod 3 and reading the coefficients starting with the constant term. 2
1, 12, 111, 1002, 12021, 111222, 1001001, 12012012, 111111111, 1000000002, 12000000021, 111000000222, 1002000002001, 12021000021012, 111222000222111, 1001001002002002, 12012012021021021, 111111111222222222, 1000000001000000001, 12000000012000000012, 111000000111000000111 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Arises in the study of a cellular automaton whose cells are in one of three states: 0, 1, or 2.

LINKS

Table of n, a(n) for n=0..20.

Index entries for sequences related to cellular automata

EXAMPLE

The first few polynomials are:

1

1+2*x

1+x+x^2

1+2*x^3

1+2*x+2*x^3+x^4

1+x+x^2+2*x^3+2*x^4+2*x^5

1+x^3+x^6

1+2*x+x^3+2*x^4+x^6+2*x^7

1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8

1+2*x^9

1+2*x+2*x^9+x^10

1+x+x^2+2*x^9+2*x^10+2*x^11

1+2*x^3+2*x^9+x^12

...

MAPLE

M:=20;

F:=1+2*x mod 3;

g:=n->expand(F^n) mod 3;

g2:=n->series(g(n), x, M+6);

for n from 0 to M do lprint(seriestolist(g2(n))); od:

CROSSREFS

Cf. A255285, A255286, A182069.

Sequence in context: A066042 A153597 A036733 * A123933 A199691 A077754

Adjacent sequences:  A253088 A253089 A253090 * A253092 A253093 A253094

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 13 2015

STATUS

approved

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Last modified May 11 21:35 EDT 2021. Contains 343808 sequences. (Running on oeis4.)