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A324474
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Nonzero ternary words such that any non-initial 1 is preceded by 0, and any non-initial 2 is preceded by 00.
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2
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1, 2, 10, 20, 100, 101, 200, 201, 1000, 1001, 1002, 1010, 2000, 2001, 2002, 2010, 10000, 10001, 10002, 10010, 10020, 10100, 10101, 20000, 20001, 20002, 20010, 20020, 20100, 20101, 100000, 100001, 100002, 100010, 100020, 100100, 100101, 100200, 100201
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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This could have begun with an initial 0, but (since this is a list, and must have offset 1), we would no longer have a(1)=1, and that is needed for some related sequences.
The indices of words of the form 100...00 are 1, 3, 5, 9, 17, 31, ..., see the tribonacci numbers A000213.
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LINKS
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EXAMPLE
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The initial terms, as a list:
1
2
10
20
100
101
200
201
1000
1001
1002
1010
2000
2001
2002
2010
10000
...
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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