A276104 Lexicographically first sequence (with no duplicate term) where all the digits "1" are separated by two digits.

1, 2, 3, 10, 4, 12, 5, 13, 6, 14, 7, 15, 8, 16, 9, 17, 21, 20, 18, 31, 22, 19, 31, 23, 100, 102, 103, 104, 105, 106, 107, 108, 109, 120, 122, 123, 124, 125, 126, 127, 128, 129, 130, 132, 133, 134, 135, 136, 137, 138, 139, 140, 142, 143, 144, 145, 146, 147, 148, 149, 150

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.

Links

Table of n, a(n) for n=1..61.

Example

To match the infinite digit-pattern 1..1..1..1..1..1.. (etc.) one must use the integer 10 after the third term (which is 3), then use the integer 4, then use the integer 12 (as 11 is forbidden: no integer with consecutive 1's is allowed), etc.

Crossrefs

Sequence in context: A307591 A031275 A306465 * A329804 A274299 A119023

Adjacent sequences: A276101 A276102 A276103 * A276105 A276106 A276107

Keyword

nonn,base

Author

Eric Angelini, Aug 18 2016

Status

approved