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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 7 |
| 5 | 36 |
| 6 | 168 |
| 7 | 736 |
| 8 | 3151 |
| 9 | 13190 |
| 10 | 54938 |
| 11 | 226597 |
| 12 | 934200 |
| 13 | 3831219 |
| 14 | 15723801 |
| 15 | 64313623 |
| 16 | 263316219 |
| 17 | 1075420890 |
| 18 | 4396310382 |
| 19 | 17937457304 |
| 20 | 73247306563 |
| 21 | 298635873550 |
| 22 | 1218428664338 |