Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,3.

A037604

Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,3.

Terms

    a(0) =1a(1) =6a(2) =27a(3) =109a(4) =438a(5) =1755a(6) =7021a(7) =28086a(8) =112347a(9) =449389a(10) =1797558a(11) =7190235a(12) =28760941a(13) =115043766a(14) =460175067a(15) =1840700269a(16) =7362801078a(17) =29451204315a(18) =117804817261a(19) =471219269046

External references