This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A199979 #13 Aug 03 2014 14:37:25
%S A199979 1,111,1111,11111,111111,1111111,11111111,111111111,1111111111,
%T A199979 11111111111,111111111111,1111111111111,11111111111111,
%U A199979 111111111111111,1111111111111111,11111111111111111,111111111111111111,11111111111111111111,111111111111111111111
%N A199979 Nonprime numbers whose multiplicative digital root is 1.
%C A199979 1 and the composite repunits.
%C A199979 Number of 1's in a(n) is in A179005. Complement of A004022 with respect to A002275.
%e A199979 1111 has a multiplicative digital root of 1 and it is the product of 11 and 101, therefore it is in the sequence.
%e A199979 11 has a multiplicative digital root of 1 but it is a prime number and therefore it is not in the sequence.
%t A199979 Select[Table[(10^n - 1)/9, {n, 20}], Not[PrimeQ[#]] &] (* _Alonso del Arte_, Nov 23 2011 *)
%Y A199979 Cf. A004022 (primes whose multiplicative digital root is 1).
%K A199979 nonn,base
%O A199979 1,2
%A A199979 _Jaroslav Krizek_, Nov 13 2011