This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 11 |
| 5 | 33 |
| 6 | 99 |
| 7 | 239 |
| 8 | 717 |
| 9 | 2151 |
| 10 | 2629 |
| 11 | 4649 |
| 12 | 7887 |
| 13 | 13947 |
| 14 | 23661 |
| 15 | 41841 |
| 16 | 51139 |
| 17 | 153417 |
| 18 | 460251 |
| 19 | 909091 |
| 20 | 1111111 |
| 21 | 2727273 |
| 22 | 3333333 |
| 23 | 8181819 |
| 24 | 9999999 |
| 25 | 10000001 |
| 26 | 12222221 |
| 27 | 30000003 |
| 28 | 36666663 |
| 29 | 90000009 |
| 30 | 109999989 |
| 31 | 217272749 |
| 32 | 651818247 |