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 | 17 |
| 3 | 289 |
| 4 | 4913 |
| 5 | 83521 |
| 6 | 1419857 |
| 7 | 5846759 |
| 8 | 24054337 |
| 9 | 24137569 |
| 10 | 99394903 |
| 11 | 408923729 |
| 12 | 410338673 |
| 13 | 1689713351 |
| 14 | 6951703393 |
| 15 | 6975757441 |
| 16 | 28725126967 |
| 17 | 118178957681 |
| 18 | 118285781329 |
| 19 | 118587876497 |
| 20 | 486643291847 |
| 21 | 488327158439 |