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 | 6 |
| 2 | 39 |
| 3 | 268 |
| 4 | 1905 |
| 5 | 13842 |
| 6 | 102123 |
| 7 | 761880 |
| 8 | 5732325 |
| 9 | 43417630 |
| 10 | 330620895 |
| 11 | 2528772132 |
| 12 | 19412942809 |
| 13 | 149497184298 |
| 14 | 1154365194195 |
| 15 | 8934458916912 |
| 16 | 69291946278861 |
| 17 | 538372925816886 |
| 18 | 4189702003359687 |
| 19 | 32651982699233340 |
| 20 | 254800541773725633 |
| 21 | 1990683254889381954 |