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 | 9 |
| 2 | 1782 |
| 3 | 2160 |
| 4 | 5400 |
| 5 | 13104 |
| 6 | 52141320 |
| 7 | 117641160 |
| 8 | 173365920 |
| 9 | 6829038720 |
| 10 | 12415092480 |
| 11 | 13356796320 |
| 12 | 104381747712 |
| 13 | 513480135168 |
| 14 | 1377031864320 |
| 15 | 6578372828160 |
| 16 | 26896578508800 |
| 17 | 294208373809152 |
| 18 | 1447285170659328 |
| 19 | 3151812152130048 |
| 20 | 7734746166732288 |