123456654321
domain: N
Appears in sequences
- Concatenation of sequence (1, 2, ..., floor((n-1)/2), floor(n/2), floor(n/2)-1, ..., 1) for n >= 1.at n=11A007907
- Concatenation of the numbers from 1 to n with numbers from n down to 1.at n=5A259937
- The concatenation of 123456...n and the reverse of this number.at n=5A261138
- Multiplication of pair of contiguous repunits, i.e., (0*1, 1*11, 11*111, 111*1111, 1111*11111, ...).at n=6A274766