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 | 0 |
| 5 | 15 |
| 6 | 3525 |
| 7 | 98473 |
| 8 | 1237434 |
| 9 | 9821400 |
| 10 | 57367112 |
| 11 | 268378248 |
| 12 | 1059987987 |
| 13 | 3661533037 |
| 14 | 11341971885 |
| 15 | 32090198922 |
| 16 | 84099053568 |
| 17 | 206386405560 |
| 18 | 478423135296 |
| 19 | 1054963957500 |
| 20 | 2225704950054 |
| 21 | 4514320792971 |
| 22 | 8838377453829 |