12131214

Appears in sequences

• a(n+1) = concatenation of a(n) and a(n)+1, with a(0)=1.at n=3A033564
• Apply the morphism 1 -> 12, 2 -> 13, 3 -> 14, 4 -> 1 n times to 1, and concatenate the resulting string.at n=3A317955