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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 56 |
| 6 | 300 |
| 7 | 1487 |
| 8 | 7041 |
| 9 | 32381 |
| 10 | 146017 |
| 11 | 649395 |
| 12 | 2859231 |
| 13 | 12494914 |
| 14 | 54291912 |
| 15 | 234860677 |
| 16 | 1012433965 |
| 17 | 4352210327 |
| 18 | 18666918033 |
| 19 | 79916230409 |
| 20 | 341615895659 |
| 21 | 1458457275715 |
| 22 | 6220016154525 |
| 23 | 26503542364381 |
| 24 | 112847001503099 |
| 25 | 480173686483581 |