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 | 1 |
| 2 | 0 |
| 3 | 6 |
| 4 | 12 |
| 5 | 320 |
| 6 | 2190 |
| 7 | 51492 |
| 8 | 685496 |
| 9 | 17286768 |
| 10 | 348213690 |
| 11 | 9956411300 |
| 12 | 266065478052 |
| 13 | 8737396913544 |
| 14 | 287741445880070 |
| 15 | 10816320294520860 |
| 16 | 420123621828718320 |
| 17 | 17913098835916877792 |
| 18 | 798053882730994171890 |
| 19 | 38192029991097097185108 |
| 20 | 1914946396460982552420380 |