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 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 120960 |
| 11 | 2661120 |
| 12 | 27941760 |
| 13 | 536215680 |
| 14 | 6901614720 |
| 15 | 90084234240 |
| 16 | 1540714855680 |
| 17 | 33110649411840 |
| 18 | 554845922991360 |
| 19 | 8393918663370240 |
| 20 | 141081442901118720 |
| 21 | 2869353360741853440 |