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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 90 |
| 5 | 1305 |
| 6 | 15713 |
| 7 | 376768 |
| 8 | 6163324 |
| 9 | 176787369 |
| 10 | 3769360335 |
| 11 | 142364319636 |
| 12 | 3152514811878 |
| 13 | 154718778284161 |
| 14 | 4340009168261557 |
| 15 | 210971169749009040 |
| 16 | 7281661102087491416 |
| 17 | 435659030617933827153 |
| 18 | 14181101408651996188995 |