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 | 6 |
| 4 | 23 |
| 5 | 103 |
| 6 | 513 |
| 7 | 2763 |
| 8 | 15816 |
| 9 | 95109 |
| 10 | 595873 |
| 11 | 3865396 |
| 12 | 25837360 |
| 13 | 177275162 |
| 14 | 1244621410 |
| 15 | 8918587896 |
| 16 | 65085848546 |
| 17 | 482852672433 |
| 18 | 3635811839722 |
| 19 | 27749901618649 |
| 20 | 214430320809516 |
| 21 | 1675833302839457 |
| 22 | 13234389150662469 |
| 23 | 105525920568921495 |
| 24 | 848962775349348810 |