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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 96 |
| 6 | 330 |
| 7 | 1066 |
| 8 | 3451 |
| 9 | 11581 |
| 10 | 39264 |
| 11 | 132784 |
| 12 | 446460 |
| 13 | 1497108 |
| 14 | 5023696 |
| 15 | 16878488 |
| 16 | 56739141 |
| 17 | 190697893 |
| 18 | 640763258 |
| 19 | 2152824662 |
| 20 | 7233281108 |
| 21 | 24304468132 |
| 22 | 81666680202 |
| 23 | 274410023170 |
| 24 | 922040339607 |
| 25 | 3098121457769 |