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 | 16 |
| 3 | 162 |
| 4 | 1536 |
| 5 | 15000 |
| 6 | 155520 |
| 7 | 1728720 |
| 8 | 20643840 |
| 9 | 264539520 |
| 10 | 3628800000 |
| 11 | 53129260800 |
| 12 | 827714764800 |
| 13 | 13680764697600 |
| 14 | 239217231052800 |
| 15 | 4413400992000000 |
| 16 | 85699747381248000 |
| 17 | 1747492334235648000 |
| 18 | 37338643451805696000 |
| 19 | 834363743704178688000 |