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 | 4 |
| 4 | 3 |
| 5 | 20 |
| 6 | 43 |
| 7 | 136 |
| 8 | 711 |
| 9 | 1606 |
| 10 | 12653 |
| 11 | 36852 |
| 12 | 250673 |
| 13 | 1212498 |
| 14 | 6016715 |
| 15 | 45081688 |
| 16 | 196537387 |
| 17 | 1789229594 |
| 18 | 8963510621 |
| 19 | 76863454428 |
| 20 | 512264745473 |
| 21 | 3744799424978 |
| 22 | 32870550965259 |
| 23 | 219159966518160 |
| 24 | 2257073412153459 |
| 25 | 15778075163815474 |
| 26 | 165231652982941085 |