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 | 6 |
| 2 | 42 |
| 3 | 224 |
| 4 | 1008 |
| 5 | 4032 |
| 6 | 14784 |
| 7 | 50688 |
| 8 | 164736 |
| 9 | 512512 |
| 10 | 1537536 |
| 11 | 4472832 |
| 12 | 12673024 |
| 13 | 35094528 |
| 14 | 95256576 |
| 15 | 254017536 |
| 16 | 666796032 |
| 17 | 1725825024 |
| 18 | 4410441728 |
| 19 | 11142168576 |
| 20 | 27855421440 |
| 21 | 68975329280 |
| 22 | 169303080960 |
| 23 | 412216197120 |