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 | 3 |
| 4 | 12 |
| 5 | 69 |
| 6 | 278 |
| 7 | 2524 |
| 8 | 27024 |
| 9 | 250688 |
| 10 | 3721984 |
| 11 | 56111104 |
| 12 | 835883008 |
| 13 | 17920733184 |
| 14 | 437473529856 |
| 15 | 9120031211520 |
| 16 | 270263516958720 |