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 | 119 |
| 6 | 708 |
| 7 | 4914 |
| 8 | 38977 |
| 9 | 347808 |
| 10 | 3448482 |
| 11 | 37610495 |
| 12 | 447485376 |
| 13 | 5767807974 |
| 14 | 80062182733 |
| 15 | 1190713519497 |
| 16 | 18889300119942 |
| 17 | 318385578137273 |
| 18 | 5682173514985293 |
| 19 | 107042610409389945 |
| 20 | 2122634830121877061 |
| 21 | 44196021893249998467 |
| 22 | 964038681151139896083 |