The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 33 |
| 4 | 99 |
| 5 | 111 |
| 6 | 141 |
| 7 | 171 |
| 8 | 303 |
| 9 | 393 |
| 10 | 535 |
| 11 | 717 |
| 12 | 777 |
| 13 | 979 |
| 14 | 1441 |
| 15 | 1771 |
| 16 | 3003 |
| 17 | 3223 |
| 18 | 3663 |
| 19 | 5335 |
| 20 | 7447 |
| 21 | 9009 |
| 22 | 9339 |
| 23 | 9999 |
| 24 | 11011 |
| 25 | 11811 |
| 26 | 11911 |
| 27 | 12121 |
| 28 | 12321 |
| 29 | 12621 |
| 30 | 13531 |
| 31 | 14041 |
| 32 | 14541 |
| 33 | 14841 |
| 34 | 17671 |
| 35 | 18381 |
| 36 | 18681 |
| 37 | 19791 |
| 38 | 30303 |
| 39 | 31713 |
| 40 | 32223 |
[1,9,33,99,111,141,171,303,393,535,717,777,979, 1441,1771,3003,3223,3663,5335,7447,9009,9339,9999, 11011,11811,11911,12121,12321,12621,13531,14041, 14541,14841,17671,18381,18681,19791,30303,31713, 32223] |