A125098 Values occurring in A123895.

0, 1, 10, 11, 12, 100, 101, 102, 110, 111, 112, 120, 121, 122, 123, 1000, 1001, 1002, 1010, 1011, 1012, 1020, 1021, 1022, 1023, 1100, 1101, 1102, 1110, 1111, 1112, 1120, 1121, 1122, 1123, 1200, 1201, 1202, 1203, 1210, 1211, 1212, 1213, 1220, 1221, 1222

Offset: 0

Author

Franklin T. Adams-Watters, Nov 20 2006

Keywords

• base
• easy
• nonn

Comments

Also, numbers n such that A123895(n) = n. Each digit is either 0, has occurred before, or is one more than the largest preceding digit. The number of k-digit numbers in this sequence is A005493(k-1) for 2<=k<=9. The initial 0 prevents a match for k=1; later values fall short because there are no digits beyond 9 available in decimal.

Links

• R. J. Mathar, Table of n, a(n) for n = 0..876

Crossrefs

Cf. A123895, A005493, A123902.

Programs

Maple

bag := {} ;
for i from 0 to 99999 do
    bag := bag union {A123895(i)} ;
end do:
sort(convert(bag,list)) ; # R. J. Mathar, Dec 10 2015

Mathematica

f[n_] := Block[{d = Prepend[IntegerDigits@ n, 0], a, b, w}, b = DeleteDuplicates@ d; a = Range[0, Length@ b]; w = FromDigits@ Flatten[Part[a, FirstPosition[b, #]] & /@ d]; w]; Union@ Table[f@n, {n, 0, 10^4}] (* Michael De Vlieger, Dec 09 2015, Version 10 *)