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 | 7 |
| 4 | 26 |
| 5 | 98 |
| 6 | 387 |
| 7 | 1589 |
| 8 | 6688 |
| 9 | 28676 |
| 10 | 124880 |
| 11 | 550926 |
| 12 | 2456831 |
| 13 | 11056693 |
| 14 | 50152457 |
| 15 | 229050621 |
| 16 | 1052393802 |
| 17 | 4861062466 |
| 18 | 22559964766 |
| 19 | 105144660498 |
| 20 | 491922058878 |
| 21 | 2309456782464 |
| 22 | 10876596029574 |
| 23 | 51372213424194 |
| 24 | 243283513468707 |
| 25 | 1154929327702775 |
| 26 | 5495105429597720 |