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 | 6 |
| 2 | 120 |
| 3 | 2394 |
| 4 | 47760 |
| 5 | 952806 |
| 6 | 19008360 |
| 7 | 379214394 |
| 8 | 7565279520 |
| 9 | 150926376006 |
| 10 | 3010962240600 |
| 11 | 60068318435994 |
| 12 | 1198355406479280 |
| 13 | 23907039811149606 |
| 14 | 476942440816512840 |
| 15 | 9514941776519107194 |
| 16 | 189821893089565631040 |