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 | 3 |
| 2 | 15 |
| 3 | 99 |
| 4 | 801 |
| 5 | 7623 |
| 6 | 83079 |
| 7 | 1017495 |
| 8 | 13808097 |
| 9 | 205374123 |
| 10 | 3318673599 |
| 11 | 57845821707 |
| 12 | 1081091446785 |
| 13 | 21553820597871 |
| 14 | 456410531639799 |
| 15 | 10225931132021247 |
| 16 | 241609515712343361 |
| 17 | 6002109578246918355 |
| 18 | 156360266121378584943 |
| 19 | 4261404847790207796147 |