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 | 67 |
| 3 | 477 |
| 4 | 3363 |
| 5 | 23741 |
| 6 | 168451 |
| 7 | 1202685 |
| 8 | 8641539 |
| 9 | 62470141 |
| 10 | 454164483 |
| 11 | 3319054333 |
| 12 | 24371503107 |
| 13 | 179736723453 |
| 14 | 1330803769347 |
| 15 | 9889323810813 |
| 16 | 73733148770307 |
| 17 | 551423090098173 |
| 18 | 4135500638060547 |