A135479 Sorted list of primitive strings that can be obtained by starting with 123 and repeatedly doubling any substring in place.

123, 12123, 12323, 123123, 1212123, 1212323, 1232323, 12123123, 12312123, 12312323, 12313123, 12323123, 121212123, 121212323, 121232123, 121232323, 123123123, 123212323, 123232323, 1212123123, 1212312123, 1212312323, 1212313123, 1212323123, 1231212123

Offset: 1

Author

N. J. A. Sloane, Feb 22 2008

Keywords

• nonn
• easy

Comments

The list contains A135017(n) strings of length n.

The subset of strings in A135475 that contain no repeated symbol.

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..11498
• Index entries for doubling substrings