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 | 2 |
| 2 | 9 |
| 3 | 50 |
| 4 | 295 |
| 5 | 1792 |
| 6 | 11088 |
| 7 | 69498 |
| 8 | 439791 |
| 9 | 2803658 |
| 10 | 17978389 |
| 11 | 115837592 |
| 12 | 749321716 |
| 13 | 4863369656 |
| 14 | 31655226108 |
| 15 | 206549749930 |
| 16 | 1350638103791 |
| 17 | 8848643946550 |
| 18 | 58069093513635 |
| 19 | 381650672631330 |
| 20 | 2511733593767295 |
| 21 | 16550500379912640 |
| 22 | 109176697072162080 |