A262288 a(0)=0; thereafter add the smallest positive number that is not a substring.

0, 1, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 19, 21, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 83, 84, 85, 86, 87, 88, 89, 90, 91, 93, 94, 95, 96, 97, 98, 99, 100, 102, 105, 107

Offset: 0

Author

N. J. A. Sloane, Sep 19 2015

Keywords

• nonn
• base

Examples

			In a(13) = 19 we can see a 1 but no 2, so a(14) = 19+2 = 21. Now we can see a 1 and a 2 but no 3, so a(15) = 21+3 = 24.
		

Crossrefs

Decimal analog of A260273.

Cf. A261793.

Programs

Mathematica

r[n_]:=Rest[Subsets[IntegerDigits[n]]];
s[n_]:=Union[FromDigits/@r[n]];firstN[0]=1;firstN[1]=2;
firstN[n_]:=Min[Select[Range[Last[s[n]]],FreeQ[s[n],#]&]];
nextTerm[n_]:=n+firstN[n];FoldList[nextTerm[#]&,0,Range@87] (* Ivan N. Ianakiev, Sep 20 2015 *)

Formula

a(n) = A261793(n) for n >= 1. - Georg Fischer, Oct 30 2018

Extensions

Typo in a(61) corrected by Ivan N. Ianakiev, Sep 20 2015