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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 48 |
| 6 | 217 |
| 7 | 1005 |
| 8 | 4878 |
| 9 | 24218 |
| 10 | 123021 |
| 11 | 634995 |
| 12 | 3323963 |
| 13 | 17596131 |
| 14 | 94053675 |
| 15 | 506865965 |
| 16 | 2751093957 |
| 17 | 15025119759 |
| 18 | 82511460766 |
| 19 | 455331632088 |
| 20 | 2523688452540 |
| 21 | 14042621802676 |
| 22 | 78415665739800 |
| 23 | 439298161502112 |
| 24 | 2468288819015277 |