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 | 3 |
| 4 | 48 |
| 5 | 360 |
| 6 | 2057 |
| 7 | 10276 |
| 8 | 47552 |
| 9 | 209871 |
| 10 | 898168 |
| 11 | 3765080 |
| 12 | 15560725 |
| 13 | 63681228 |
| 14 | 258826128 |
| 15 | 1046920155 |
| 16 | 4220390592 |
| 17 | 16973219016 |
| 18 | 68148598817 |
| 19 | 273305152756 |
| 20 | 1095189435488 |
| 21 | 4386195036135 |
| 22 | 17559755662600 |
| 23 | 70280167711928 |
| 24 | 281233465458733 |
| 25 | 1125242449638300 |
| 26 | 4501812479503152 |