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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 22 |
| 5 | 181 |
| 6 | 5814 |
| 7 | 1488565 |
| 8 | 12194330294 |
| 9 | 25573364166211253 |
| 10 | 439347050970302571643057846 |
| 11 | 15829145720289447797800874537321282579904181 |
| 12 | 9797766637414564027586288536574448245991597197836000123235901011048118 |