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 | 1 |
| 3 | 5 |
| 4 | 10 |
| 5 | 56 |
| 6 | 178 |
| 7 | 1202 |
| 8 | 5296 |
| 9 | 42272 |
| 10 | 238816 |
| 11 | 2204480 |
| 12 | 15214480 |
| 13 | 159575936 |
| 14 | 1301989648 |
| 15 | 15299174672 |
| 16 | 144118832896 |
| 17 | 1875796977152 |
| 18 | 20040052293376 |
| 19 | 286222128454400 |
| 20 | 3419989086092800 |
| 21 | 53183132405282816 |
| 22 | 702831038438522368 |