The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 31 |
| 3 | 99 |
| 4 | 201 |
| 5 | 301 |
| 6 | 211 |
| 7 | 311 |
| 8 | 221 |
| 9 | 2001 |
| 10 | 3001 |
| 11 | 1101 |
| 12 | 2101 |
| 13 | 3101 |
| 14 | 1201 |
| 15 | 2201 |
| 16 | 1301 |
| 17 | 2011 |
| 18 | 3011 |
| 19 | 2111 |
| 20 | 3111 |
| 21 | 1211 |
| 22 | 2211 |
| 23 | 2021 |
| 24 | 2121 |
| 25 | 2102 |
| 26 | 2202 |
| 27 | 6501 |
| 28 | 20001 |
| 29 | 30001 |
| 30 | 11001 |
| 31 | 21001 |
| 32 | 31001 |
| 33 | 12001 |
| 34 | 22001 |
| 35 | 13001 |
| 36 | 20101 |
| 37 | 30101 |
| 38 | 11101 |
| 39 | 21101 |
| 40 | 31101 |
[21,31,99,201,301,211,311,221,2001,3001,1101,2101, 3101,1201,2201,1301,2011,3011,2111,3111,1211,2211, 2021,2121,2102,2202,6501,20001,30001,11001,21001, 31001,12001,22001,13001,20101,30101,11101,21101, 31101] |