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 | 24 |
| 5 | 119 |
| 6 | 694 |
| 7 | 4582 |
| 8 | 33325 |
| 9 | 261853 |
| 10 | 2191902 |
| 11 | 19344408 |
| 12 | 178582940 |
| 13 | 1713999264 |
| 14 | 17019444969 |
| 15 | 174149184184 |
| 16 | 1830279810276 |
| 17 | 19703572779755 |
| 18 | 216769635980879 |
| 19 | 2432308876304981 |
| 20 | 27788506478197951 |
| 21 | 322770995262901091 |
| 22 | 3806657237502632706 |
| 23 | 45532086120583546634 |