44444444domain: NAppears in sequencesa(n) = 4*(10^n - 1)/9.at n=8A002278Nonsquarefree numbers obtained by repeating a single digit.at n=26A077572The smallest number that has more copies of some digit than all previous terms of the sequence put together.at n=31A179310Repdigit self-numbers that are not in A337208.at n=8A382167