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 | 1 |
| 3 | 5 |
| 4 | 38 |
| 5 | 357 |
| 6 | 3832 |
| 7 | 45189 |
| 8 | 572378 |
| 9 | 7676653 |
| 10 | 107971691 |
| 11 | 1581714400 |
| 12 | 24012849880 |
| 13 | 376361077578 |
| 14 | 6071985730614 |
| 15 | 100602798234000 |
| 16 | 1708558136679750 |
| 17 | 29698002444820760 |
| 18 | 527661478169200755 |
| 19 | 9573199146196780335 |
| 20 | 177192815265794698364 |
| 21 | 3343432166097650920872 |