a(n) = 2*10^n + 3.

Terms

a(0) =5a(1) =23a(2) =203a(3) =2003a(4) =20003a(5) =200003a(6) =2000003a(7) =20000003a(8) =200000003a(9) =2000000003a(10) =20000000003a(11) =200000000003