a(n) = 10^n+2*n.

Terms

a(0) =1a(1) =12a(2) =104a(3) =1006a(4) =10008a(5) =100010a(6) =1000012a(7) =10000014a(8) =100000016a(9) =1000000018a(10) =10000000020a(11) =100000000022