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) |
|---|---|
| 2 | 3 |
| 3 | 12 |
| 4 | 40 |
| 5 | 120 |
| 6 | 336 |
| 7 | 896 |
| 8 | 2304 |
| 9 | 5760 |
| 10 | 14080 |
| 11 | 33792 |
| 12 | 79872 |
| 13 | 186368 |
| 14 | 430080 |
| 15 | 983040 |
| 16 | 2228224 |
| 17 | 5013504 |
| 18 | 11206656 |
| 19 | 24903680 |
| 20 | 55050240 |
| 21 | 121110528 |
| 22 | 265289728 |
| 23 | 578813952 |
| 24 | 1258291200 |
| 25 | 2726297600 |
| 26 | 5888802816 |
| 27 | 12683575296 |
| 28 | 27246198784 |
| 29 | 58384711680 |
| 30 | 124822487040 |