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 | 45 |
| 4 | 448 |
| 5 | 5825 |
| 6 | 95796 |
| 7 | 1926043 |
| 8 | 45944256 |
| 9 | 1269187137 |
| 10 | 39840825700 |
| 11 | 1400286658331 |
| 12 | 54462564354672 |
| 13 | 2321934762267601 |
| 14 | 107664031299459012 |
| 15 | 5393893268767761675 |
| 16 | 290341440380472614656 |
| 17 | 16710435419661861992705 |
| 18 | 1024009456958258244673860 |