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 | 5 |
| 3 | 32 |
| 4 | 233 |
| 5 | 1833 |
| 6 | 15180 |
| 7 | 130392 |
| 8 | 1151057 |
| 9 | 10378883 |
| 10 | 95182445 |
| 11 | 885053524 |
| 12 | 8324942620 |
| 13 | 79071217228 |
| 14 | 757310811912 |
| 15 | 7305728683824 |
| 16 | 70923966744609 |
| 17 | 692370887676567 |
| 18 | 6792525607165935 |
| 19 | 66933512163735000 |
| 20 | 662190712902022017 |
| 21 | 6574831459429388169 |
| 22 | 65494637699437417584 |