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 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 53 |
| 6 | 217 |
| 7 | 1014 |
| 8 | 5335 |
| 9 | 31240 |
| 10 | 201608 |
| 11 | 1422074 |
| 12 | 10886503 |
| 13 | 89903100 |
| 14 | 796713190 |
| 15 | 7541889195 |
| 16 | 75955177642 |
| 17 | 810925547354 |
| 18 | 9148832109645 |
| 19 | 108759758865725 |
| 20 | 1358836180945243 |
| 21 | 17801039909762186 |
| 22 | 243992799075850037 |
| 23 | 3492329741309417600 |
| 24 | 52105418376516869150 |
| 25 | 809029109658971635142 |