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 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 36 |
| 4 | 210 |
| 5 | 1225 |
| 6 | 7140 |
| 7 | 41616 |
| 8 | 242556 |
| 9 | 1413721 |
| 10 | 8239770 |
| 11 | 48024900 |
| 12 | 279909630 |
| 13 | 1631432881 |
| 14 | 9508687656 |
| 15 | 55420693056 |
| 16 | 323015470680 |
| 17 | 1882672131025 |
| 18 | 10973017315470 |
| 19 | 63955431761796 |
| 20 | 372759573255306 |
| 21 | 2172602007770041 |