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 | 40 |
| 2 | 542 |
| 3 | -62960 |
| 4 | -4238708 |
| 5 | 96898400 |
| 6 | 26298701320 |
| 7 | 436837009600 |
| 8 | -177294701591920 |
| 9 | -10789176512931200 |
| 10 | 1256633088041014240 |
| 11 | 164414811028452665600 |
| 12 | -8048103437483217101120 |
| 13 | -2409334578316563726502400 |
| 14 | 14320231546481618948708480 |
| 15 | 36259873035884206674901888000 |