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 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 46 |
| 6 | 139 |
| 7 | 511 |
| 8 | 1891 |
| 9 | 6707 |
| 10 | 24366 |
| 11 | 91840 |
| 12 | 348236 |
| 13 | 1320309 |
| 14 | 5056414 |
| 15 | 19565036 |
| 16 | 76077330 |
| 17 | 296994727 |
| 18 | 1165438921 |
| 19 | 4594915664 |
| 20 | 18181401268 |
| 21 | 72176250259 |
| 22 | 287450966807 |
| 23 | 1148178877918 |
| 24 | 4598148937702 |
| 25 | 18458646079181 |
| 26 | 74267340207247 |