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 | 4 |
| 2 | 30 |
| 3 | 272 |
| 4 | 2695 |
| 5 | 28080 |
| 6 | 302064 |
| 7 | 3321120 |
| 8 | 37095201 |
| 9 | 419276660 |
| 10 | 4782798020 |
| 11 | 54960207120 |
| 12 | 635339153865 |
| 13 | 7380876649216 |
| 14 | 86101923008160 |
| 15 | 1007980225327680 |
| 16 | 11836181297108565 |
| 17 | 139353762142502100 |