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 | 13 |
| 3 | 109 |
| 4 | 877 |
| 5 | 7021 |
| 6 | 56173 |
| 7 | 449389 |
| 8 | 3595117 |
| 9 | 28760941 |
| 10 | 230087533 |
| 11 | 1840700269 |
| 12 | 14725602157 |
| 13 | 117804817261 |
| 14 | 942438538093 |
| 15 | 7539508304749 |
| 16 | 60316066437997 |
| 17 | 482528531503981 |
| 18 | 3860228252031853 |
| 19 | 30881826016254829 |
| 20 | 247054608130038637 |
| 21 | 1976436865040309101 |
| 22 | 15811494920322472813 |