1123456

Appears in sequences

• a(n) = min{p + q + r + ...} where p,q,r,... are distinct unary numbers - containing only ones, i.e., of the form (10^k - 1)/9 - formed by using a total of n ones.at n=21A110380
• Number of circular binary sequences of length n with an odd number of 0's and no three consecutive 1's.at n=23A366045
• a(1)=1, and for n>1, a(n) = a(n-1) concatenated with the length of the decimal representation of a(n-1).at n=6A383429