Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,2,1.

A037567

Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,2,1.

Terms

    a(0) =2a(1) =22a(2) =221a(3) =2212a(4) =22122a(5) =221221a(6) =2212212a(7) =22122122a(8) =221221221a(9) =2212212212a(10) =22122122122a(11) =221221221221

External references