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 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 20 |
| 6 | 104 |
| 7 | 775 |
| 8 | 6140 |
| 9 | 55427 |
| 10 | 553802 |
| 11 | 6087992 |
| 12 | 72994152 |
| 13 | 948103477 |
| 14 | 13262133736 |
| 15 | 198769630061 |
| 16 | 3177862894922 |
| 17 | 53984653965996 |
| 18 | 971068821144112 |
| 19 | 18438722595913195 |
| 20 | 368558842844143268 |
| 21 | 7735520783692157215 |
| 22 | 170095060428041137778 |
| 23 | 3910332719957508452016 |
| 24 | 93806427360751009531632 |