Powers of sqrt(10) rounded down.

Terms

a(0) =1a(1) =3a(2) =10a(3) =31a(4) =100a(5) =316a(6) =1000a(7) =3162a(8) =10000a(9) =31622a(10) =100000a(11) =316227a(12) =1000000a(13) =3162277a(14) =10000000a(15) =31622776a(16) =100000000a(17) =316227766a(18) =1000000000a(19) =3162277660a(20) =10000000000a(21) =31622776601a(22) =100000000000a(23) =316227766016a(24) =1000000000000