Number of squares (of positive integers) with n digits.

Terms

a(0) =3a(1) =6a(2) =22a(3) =68a(4) =217a(5) =683a(6) =2163a(7) =6837a(8) =21623a(9) =68377a(10) =216228a(11) =683772a(12) =2162278a(13) =6837722a(14) =21622777a(15) =68377223a(16) =216227767a(17) =683772233a(18) =2162277661a(19) =6837722339a(20) =21622776602a(21) =68377223398a(22) =216227766017a(23) =683772233983