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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 27 |
| 6 | 108 |
| 7 | 475 |
| 8 | 2421 |
| 9 | 13859 |
| 10 | 88254 |
| 11 | 617957 |
| 12 | 4720980 |
| 13 | 39070669 |
| 14 | 348225424 |
| 15 | 3325303894 |
| 16 | 33871280413 |
| 17 | 366573108019 |
| 18 | 4200618576106 |
| 19 | 50809739256049 |
| 20 | 646929695900154 |
| 21 | 8648812936664311 |
| 22 | 121132117170628444 |
| 23 | 1773647319453218254 |
| 24 | 27099334868109293640 |