A210423 List the positions of all digits 9 in the concatenation of all terms, not necessarily in order. This is the lexicographically earliest such sequence.
2, 9, 4, 90, 7, 91, 92, 13, 93, 17, 94, 21, 95, 25, 96, 29, 97, 28, 35, 98, 39, 99, 38, 40, 47, 900, 52, 901, 57, 902, 62, 903, 67, 904, 72, 905, 77, 906, 82, 907, 87, 908, 999, 9999, 9990, 104, 909, 106, 113, 910, 119, 911, 118, 128, 912, 134, 913, 139, 143
Offset: 1
Examples
The sequence cannot start with 1 because the first digit is not 9. Let us start with 2: the second digit is equal to 9. The third digit cannot be 3 because the third digit is not 9. So let it be 4. In the next position we now have 90 because it is the minimum number greater than 8 and starting with the digit 9. And so on.
Links
- Danny Rorabaugh, Table of n, a(n) for n = 1..1000
Extensions
a(23)-a(26) corrected by Paolo P. Lava, Apr 17 2012
Comments