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) |
|---|---|
| 3 | 6 |
| 4 | 36 |
| 5 | 210 |
| 6 | 1260 |
| 7 | 6426 |
| 8 | 3360 |
| 9 | 351000 |
| 10 | 207900 |
| 11 | 3749460 |
| 12 | 1153152 |
| 13 | 15036840 |
| 14 | 204204000 |
| 15 | 213825150 |
| 16 | 11737440 |
| 17 | 91797866160 |
| 18 | 1006485480 |
| 19 | 2310808500 |
| 20 | 4966241280 |
| 21 | 22651328700 |
| 22 | 325269404460 |
| 23 | 14266470332400 |
| 24 | 11203920000 |
| 25 | 256653797400 |
| 26 | 45843256859400 |
| 27 | 59207908359600 |
| 28 | 46822406400 |