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

0,3

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

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 *)

Crossrefs

Cf. A123895, A005493, A123902.

Sequence in context: A048024 A048002 A256523 * A239903 A244159 A171752

Adjacent sequences: A125095 A125096 A125097 * A125099 A125100 A125101

Keyword

base,easy,nonn

Author

Franklin T. Adams-Watters, Nov 20 2006

Status

approved