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 | 120 |
| 1 | 2640 |
| 2 | 28512 |
| 3 | 205920 |
| 4 | 1132560 |
| 5 | 5096520 |
| 6 | 19631040 |
| 7 | 66745536 |
| 8 | 204787440 |
| 9 | 576438720 |
| 10 | 1507608960 |
| 11 | 3700494720 |
| 12 | 8593371072 |
| 13 | 19004570640 |
| 14 | 40244973120 |
| 15 | 81980500800 |
| 16 | 161264274600 |
| 17 | 307350735120 |
| 18 | 569168028000 |
| 19 | 1026681084000 |
| 20 | 1807851474000 |
| 21 | 3113521983000 |