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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 150 |
| 5 | 3240 |
| 6 | 72030 |
| 7 | 1720320 |
| 8 | 44641044 |
| 9 | 1260000000 |
| 10 | 38584598580 |
| 11 | 1277045637120 |
| 12 | 45493302310170 |
| 13 | 1737263457785856 |
| 14 | 70841500488281250 |
| 15 | 3073706745680363520 |
| 16 | 141437374309896780360 |
| 17 | 6881573428807007600640 |
| 18 | 353052290206768309241544 |
| 19 | 19051315200000000000000000 |