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 | 7 |
| 3 | 95 |
| 4 | 1614 |
| 5 | 30718 |
| 6 | 626434 |
| 7 | 13383650 |
| 8 | 295692145 |
| 9 | 6700461777 |
| 10 | 154871912815 |
| 11 | 3637093846055 |
| 12 | 86539594779772 |
| 13 | 2081721640140460 |
| 14 | 50542732376144460 |
| 15 | 1236960716959913020 |
| 16 | 30483096737455969766 |
| 17 | 755783491624380578998 |
| 18 | 18839297079646725396450 |