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 | 0 |
| 2 | 6 |
| 3 | 120 |
| 4 | 1980 |
| 5 | 32970 |
| 6 | 584430 |
| 7 | 11204676 |
| 8 | 233098740 |
| 9 | 5254404210 |
| 10 | 127921380840 |
| 11 | 3350718545460 |
| 12 | 94062457204716 |
| 13 | 2819367702529560 |
| 14 | 89912640142178490 |
| 15 | 3040986592542420060 |
| 16 | 108752084073199561140 |
| 17 | 4101112025363285051526 |