10000000020domain: NAppears in sequencesLeast multiple of n in which the n-th digit from left is 2.at n=9A113557a(n) = 10^n+2*n.at n=10A173835Cantor's ordering of positive rational numbers, where a(n) is the balanced ternary representation of the "factorization" of the positive rational number into terms of A186285.at n=30A185169