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 | 15 |
| 5 | 48 |
| 6 | 160 |
| 7 | 549 |
| 8 | 1930 |
| 9 | 6919 |
| 10 | 25200 |
| 11 | 92976 |
| 12 | 346757 |
| 13 | 1305140 |
| 14 | 4951216 |
| 15 | 18912245 |
| 16 | 72675114 |
| 17 | 280761670 |
| 18 | 1089800270 |
| 19 | 4248149795 |
| 20 | 16623209911 |
| 21 | 65273370720 |
| 22 | 257115465600 |
| 23 | 1015719256200 |
| 24 | 4023178881540 |
| 25 | 15974388769653 |
| 26 | 63570826294760 |