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 | 16 |
| 5 | 60 |
| 6 | 260 |
| 7 | 1267 |
| 8 | 6850 |
| 9 | 40572 |
| 10 | 260812 |
| 11 | 1805646 |
| 12 | 13377274 |
| 13 | 105487540 |
| 14 | 881338060 |
| 15 | 7770957903 |
| 16 | 72060991394 |
| 17 | 700653026744 |
| 18 | 7123871583656 |
| 19 | 75561097962918 |
| 20 | 834285471737784 |
| 21 | 9570207406738352 |
| 22 | 113855103776348136 |
| 23 | 1402523725268921870 |
| 24 | 17863056512845724036 |
| 25 | 234910502414771617316 |
| 26 | 3185732802058088068444 |
| 27 | 44501675392317774477088 |