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 | 9 |
| 3 | 49 |
| 4 | 265 |
| 5 | 1281 |
| 6 | 6201 |
| 7 | 28673 |
| 8 | 131337 |
| 9 | 589873 |
| 10 | 2622729 |
| 11 | 11534337 |
| 12 | 50338105 |
| 13 | 218103809 |
| 14 | 939552777 |
| 15 | 4026533169 |
| 16 | 17180000521 |
| 17 | 73014444033 |
| 18 | 309238241337 |
| 19 | 1305670057985 |
| 20 | 5497560761865 |
| 21 | 23089744212017 |
| 22 | 96757034778633 |
| 23 | 404620279021569 |
| 24 | 1688849910733113 |