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 | 3 |
| 3 | 16 |
| 4 | 97 |
| 5 | 645 |
| 6 | 4539 |
| 7 | 33242 |
| 8 | 250715 |
| 9 | 1934131 |
| 10 | 15190377 |
| 11 | 121050779 |
| 12 | 976334857 |
| 13 | 7954909796 |
| 14 | 65378035310 |
| 15 | 541346845867 |
| 16 | 4511820592102 |
| 17 | 37819912868231 |
| 18 | 318639423484669 |
| 19 | 2696819879180630 |
| 20 | 22918021992024063 |
| 21 | 195480539889732302 |
| 22 | 1672951468057552136 |
| 23 | 14361120982757852887 |
| 24 | 123625070638172667688 |
| 25 | 1066939084577136857174 |