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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 34 |
| 5 | 206 |
| 6 | 1486 |
| 7 | 12412 |
| 8 | 117692 |
| 9 | 1248004 |
| 10 | 14625856 |
| 11 | 187638716 |
| 12 | 2614602112 |
| 13 | 39310384192 |
| 14 | 634148436104 |
| 15 | 10923398137576 |
| 16 | 200069534481616 |
| 17 | 3882002527006352 |
| 18 | 79535575126745632 |
| 19 | 1715658099715217584 |