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 | 0 |
| 4 | 1 |
| 5 | 2 |
| 6 | 12 |
| 7 | 53 |
| 8 | 250 |
| 9 | 1115 |
| 10 | 5012 |
| 11 | 22032 |
| 12 | 96746 |
| 13 | 422732 |
| 14 | 1848128 |
| 15 | 8088090 |
| 16 | 35498533 |
| 17 | 156328706 |
| 18 | 691192578 |
| 19 | 3068780449 |
| 20 | 13683070474 |
| 21 | 61267204610 |
| 22 | 275455737555 |
| 23 | 1243320744572 |
| 24 | 5633022679582 |
| 25 | 25611815936218 |
| 26 | 116840427373176 |
| 27 | 534705818846660 |
| 28 | 2454282243059471 |