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A135475
Sorted list of strings that can be obtained by starting with 123 and repeatedly doubling any substring in place.
3
123, 1123, 1223, 1233, 11123, 11223, 11233, 12123, 12223, 12233, 12323, 12333, 111123, 111223, 111233, 112123, 112223, 112233, 112323, 112333, 121123, 121223, 121233, 122123, 122223, 122233, 122323, 122333, 123123, 123223, 123233, 123323, 123333, 1111123
OFFSET
1,1
COMMENTS
The list contains A135473(n) strings of length n.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10397 (strings with length <= 12)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Feb 22 2008, Mar 16 2008
STATUS
approved