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 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 31 |
| 6 | 84 |
| 7 | 261 |
| 8 | 865 |
| 9 | 2815 |
| 10 | 9131 |
| 11 | 30339 |
| 12 | 102681 |
| 13 | 349376 |
| 14 | 1193993 |
| 15 | 4111947 |
| 16 | 14263137 |
| 17 | 49720513 |
| 18 | 174040102 |
| 19 | 611770893 |
| 20 | 2158954383 |
| 21 | 7645030641 |
| 22 | 27153898487 |
| 23 | 96719683491 |
| 24 | 345414958227 |
| 25 | 1236555046701 |
| 26 | 4436564115556 |
| 27 | 15950469680836 |
| 28 | 57455730349552 |