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 | 3 |
| 3 | 15 |
| 4 | 107 |
| 5 | 991 |
| 6 | 11267 |
| 7 | 151721 |
| 8 | 2360375 |
| 9 | 41650861 |
| 10 | 821881709 |
| 11 | 17932031225 |
| 12 | 428630422697 |
| 13 | 11138928977049 |
| 14 | 312680873171465 |
| 15 | 9428701154866535 |
| 16 | 303957777464447449 |
| 17 | 10431949496859168189 |
| 18 | 379755239311735494421 |