Apply the morphism X -> XYX, where Y=1 if X contains an odd number of 1's, otherwise Y = 2 n times to 1, and concatenate the resulting string.

A317956

Apply the morphism X -> XYX, where Y=1 if X contains an odd number of 1's, otherwise Y = 2 n times to 1, and concatenate the resulting string.

Terms

    a(0) =1a(1) =121a(2) =1211121

External references