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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 54 |
| 6 | 392 |
| 7 | 3378 |
| 8 | 34120 |
| 9 | 393738 |
| 10 | 5112406 |
| 11 | 73756026 |
| 12 | 1170482186 |
| 13 | 20263782630 |
| 14 | 380047964920 |
| 15 | 7676106365966 |
| 16 | 166114208828980 |
| 17 | 3834434324386350 |
| 18 | 94042629535109500 |
| 19 | 2442147034719168714 |
| 20 | 66942194906112161302 |
| 21 | 1931543452345335094678 |
| 22 | 58519191359163454708564 |