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) |
|---|---|
| 2 | 2 |
| 3 | 9 |
| 4 | 34 |
| 5 | 119 |
| 6 | 401 |
| 7 | 1316 |
| 8 | 4247 |
| 9 | 13532 |
| 10 | 42712 |
| 11 | 133816 |
| 12 | 416770 |
| 13 | 1291731 |
| 14 | 3987444 |
| 15 | 12266845 |
| 16 | 37627230 |
| 17 | 115125955 |
| 18 | 351467506 |
| 19 | 1070908135 |
| 20 | 3257389088 |
| 21 | 9892759091 |
| 22 | 30002923380 |
| 23 | 90879555521 |
| 24 | 274963755791 |
| 25 | 831064788976 |