21212121212
domain: N
Appears in sequences
- Two-bell analog of A028355.at n=16A028359
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,1.at n=10A037495
- a(n) is the smallest number not already present that permits the cyclic repetition of the path 1,2 of the digits in the sequence.at n=21A165300