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 | 6 |
| 3 | 44 |
| 4 | 400 |
| 5 | 4384 |
| 6 | 56448 |
| 7 | 836352 |
| 8 | 14026752 |
| 9 | 262803456 |
| 10 | 5441863680 |
| 11 | 123436892160 |
| 12 | 3044235018240 |
| 13 | 81112101027840 |
| 14 | 2322150583173120 |
| 15 | 71092846618214400 |
| 16 | 2317820965473484800 |
| 17 | 80177108784198451200 |
| 18 | 2932996578806543155200 |