Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,3.

A037590

Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,3.

Terms

    a(0) =1a(1) =4a(2) =19a(3) =77a(4) =308a(5) =1235a(6) =4941a(7) =19764a(8) =79059a(9) =316237a(10) =1264948a(11) =5059795a(12) =20239181a(13) =80956724a(14) =323826899a(15) =1295307597a(16) =5181230388a(17) =20724921555a(18) =82899686221a(19) =331598744884

External references