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 | 1 |
| 3 | 8 |
| 4 | 22 |
| 5 | 124 |
| 6 | 948 |
| 7 | 6138 |
| 8 | 50832 |
| 9 | 468144 |
| 10 | 5165280 |
| 11 | 54704880 |
| 12 | 695854080 |
| 13 | 9016051680 |
| 14 | 130427750880 |
| 15 | 1994479744320 |
| 16 | 32575206343680 |
| 17 | 555499414471680 |
| 18 | 10284817657927680 |
| 19 | 196642556903116800 |
| 20 | 3994718386866278400 |
| 21 | 84989047758544742400 |
| 22 | 1895851170953432985600 |