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 | 1 |
| 1 | 0 |
| 2 | -14 |
| 3 | -75 |
| 4 | -232 |
| 5 | -505 |
| 6 | -576 |
| 7 | 2639 |
| 8 | 36224 |
| 9 | 356319 |
| 10 | 3618800 |
| 11 | 39902159 |
| 12 | 478980864 |
| 13 | 6226992239 |
| 14 | 87178252784 |
| 15 | 1307674317375 |
| 16 | 20922789822464 |
| 17 | 355687428012479 |
| 18 | 6402373705623024 |
| 19 | 121645100408701679 |
| 20 | 2432902008176480000 |