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 | 4 |
| 2 | 4 |
| 3 | 17 |
| 4 | 17 |
| 5 | 81 |
| 6 | 81 |
| 7 | 499 |
| 8 | 499 |
| 9 | 3416 |
| 10 | 3416 |
| 11 | 24255 |
| 12 | 24255 |
| 13 | 181998 |
| 14 | 181998 |
| 15 | 1428698 |
| 16 | 1428698 |
| 17 | 11139859 |
| 18 | 11139859 |
| 19 | 89160415 |
| 20 | 89160415 |