12234567domain: NAppears in sequencesa(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=29A110380Smallest multiple of 3 such that decimals digits 1, ..., k (k = 1, ..., 9) and 0 appear in any order.at n=6A178341