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 | 9 |
| 2 | 73 |
| 3 | 561 |
| 4 | 4177 |
| 5 | 30489 |
| 6 | 219673 |
| 7 | 1568961 |
| 8 | 11138977 |
| 9 | 78754089 |
| 10 | 555184873 |
| 11 | 3905825361 |
| 12 | 27438433777 |
| 13 | 192557317689 |
| 14 | 1350342630073 |
| 15 | 9464605441761 |
| 16 | 66313273248577 |
| 17 | 464498088521289 |
| 18 | 3253012498555273 |
| 19 | 22778716884418161 |