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) |
|---|---|
| 3 | 1 |
| 4 | 5 |
| 5 | 24 |
| 6 | 122 |
| 7 | 680 |
| 8 | 4155 |
| 9 | 27776 |
| 10 | 202084 |
| 11 | 1592064 |
| 12 | 13513825 |
| 13 | 123025408 |
| 14 | 1196165886 |
| 15 | 12374422528 |
| 16 | 135740585015 |
| 17 | 1573990072320 |
| 18 | 19239037403528 |
| 19 | 247255523459072 |
| 20 | 3333340694137725 |
| 21 | 47039231504678912 |
| 22 | 693488743931379010 |
| 23 | 10661950808321949696 |
| 24 | 170659875799127955955 |