Smarandache Sequences
Smarandache sequences are any of a number of simply generated integer sequences resembling those considered in published works by Smarandache such as the consecutive number sequences and Euclid numbers. Some other "Smarandache" sequences are given below. 1. The concatenation of n copies of the integer n: 1, 22, 333, 4444, 55555, ... (OEIS A000461; Marimutha 1997). For n<=9, they have the simple formula a_n = n R_n = (n(10^n - 1))/9, where R_n is a repunit.