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A276105
Lexicographically first sequence (with no duplicate term) where all the digits "2" are separated by two digits.
0
1, 2, 3, 4, 20, 5, 21, 6, 23, 7, 24, 8, 25, 9, 26, 12, 10, 27, 32, 11, 28, 42, 13, 29, 52, 14, 200, 201, 203, 204, 205, 206, 207, 208, 209, 210, 211, 213, 214, 215, 216, 217, 218, 219, 230, 231, 233, 234, 235, 236, 237, 238, 239, 240, 241, 243, 244, 245, 246, 247, 248, 249
OFFSET
1,2
COMMENTS
The sequence is started with a(1)=1 and always extended with the smallest integer not yet used that does not lead to a contradiction.
EXAMPLE
To match the infinite digit-pattern 2..2..2..2..2..2.. (etc.) one must use the integer 20 after the fourth term (which is 4), then use the integer 5, then use the integer 21, then use the integer 6, then use the integer 23 (as 22 is forbidden: no integer with consecutive 2's is allowed), etc.
CROSSREFS
Sequence in context: A058772 A227941 A250259 * A247574 A169901 A012285
KEYWORD
nonn,base
AUTHOR
Eric Angelini, Aug 18 2016
STATUS
approved