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 | 12 |
| 3 | 156 |
| 4 | 2360 |
| 5 | 41400 |
| 6 | 831012 |
| 7 | 18832576 |
| 8 | 476200944 |
| 9 | 13301078400 |
| 10 | 406907517500 |
| 11 | 13534968927744 |
| 12 | 486470108273448 |
| 13 | 18790567023993856 |
| 14 | 776343673316956500 |
| 15 | 34165751933338828800 |
| 16 | 1595693034061797583328 |
| 17 | 78831769938218360930304 |
| 18 | 4107393289066148637198444 |