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 | 120 |
| 6 | 392 |
| 7 | 1810 |
| 8 | 10400 |
| 9 | 72228 |
| 10 | 589674 |
| 11 | 5196870 |
| 12 | 52398658 |
| 13 | 588036216 |
| 14 | 7274466172 |
| 15 | 98024173852 |
| 16 | 1427556373892 |