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 | 3 |
| 3 | 24 |
| 4 | 147 |
| 5 | 864 |
| 6 | 5043 |
| 7 | 29400 |
| 8 | 171363 |
| 9 | 998784 |
| 10 | 5821347 |
| 11 | 33929304 |
| 12 | 197754483 |
| 13 | 1152597600 |
| 14 | 6717831123 |
| 15 | 39154389144 |
| 16 | 228208503747 |
| 17 | 1330096633344 |
| 18 | 7752371296323 |
| 19 | 45184131144600 |
| 20 | 263352415571283 |
| 21 | 1534930362283104 |
| 22 | 8946229758127347 |
| 23 | 52142448186480984 |