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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 132 |
| 7 | 428 |
| 8 | 1417 |
| 9 | 4757 |
| 10 | 16119 |
| 11 | 54963 |
| 12 | 188219 |
| 13 | 646460 |
| 14 | 2224944 |
| 15 | 7668915 |
| 16 | 26461005 |
| 17 | 91371594 |
| 18 | 315689675 |
| 19 | 1091166442 |
| 20 | 3772747245 |
| 21 | 13047503222 |
| 22 | 45131078409 |
| 23 | 156129312025 |
| 24 | 540181837728 |
| 25 | 1869097588540 |
| 26 | 6467740095295 |