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 | 6 |
| 4 | 24 |
| 5 | 102 |
| 6 | 522 |
| 7 | 2954 |
| 8 | 18732 |
| 9 | 128338 |
| 10 | 961954 |
| 11 | 7701386 |
| 12 | 66224004 |
| 13 | 603532776 |
| 14 | 5838062076 |
| 15 | 59440800540 |
| 16 | 637153946792 |
| 17 | 7149716758206 |
| 18 | 83945137341802 |
| 19 | 1027214990885490 |
| 20 | 13089318802216052 |
| 21 | 173190191614971256 |
| 22 | 2377205362853637580 |
| 23 | 33775960984392259580 |