Least k such that base 10 representation of n begins at s(k), where s=A031312.

Terms

a(0) =1a(1) =16a(2) =2a(3) =36a(4) =3a(5) =56a(6) =4a(7) =76a(8) =5a(9) =96a(10) =6a(11) =17a(12) =1a(13) =37a(14) =10a(15) =57a(16) =12a(17) =77a(18) =14a(19) =246a(20) =16a(21) =276a(22) =18a(23) =306a(24) =20a(25) =336a(26) =22a(27) =366a(28) =24a(29) =396