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

A037495

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

Terms

    a(0) =2a(1) =21a(2) =212a(3) =2121a(4) =21212a(5) =212121a(6) =2121212a(7) =21212121a(8) =212121212a(9) =2121212121a(10) =21212121212a(11) =212121212121

External references