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 | 5 |
| 2 | 45 |
| 3 | 90 |
| 4 | 1530 |
| 5 | 9945 |
| 6 | 278460 |
| 7 | 3063060 |
| 8 | 113333220 |
| 9 | 566666100 |
| 10 | 566666100 |
| 11 | 23233310100 |
| 12 | 2346564320100 |
| 13 | 143140423526100 |
| 14 | 15904491502900 |
| 15 | 2051679403874100 |
| 16 | 59498702712348900 |
| 17 | 59498702712348900 |
| 18 | 11721244434332733300 |
| 19 | 363358577464314732300 |