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 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 24 |
| 4 | 114 |
| 5 | 618 |
| 6 | 3732 |
| 7 | 24702 |
| 8 | 177126 |
| 9 | 1363740 |
| 10 | 11195286 |
| 11 | 97437138 |
| 12 | 894857712 |
| 13 | 8637708858 |
| 14 | 87333790686 |
| 15 | 922203924216 |
| 16 | 10144109299146 |
| 17 | 115972625504994 |
| 18 | 1375221840671220 |
| 19 | 16884112119546534 |
| 20 | 214270296662325534 |
| 21 | 2806600053170775372 |
| 22 | 37892025089041181982 |