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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 108 |
| 6 | 544 |
| 7 | 3264 |
| 8 | 23040 |
| 9 | 171072 |
| 10 | 1409664 |
| 11 | 12916224 |
| 12 | 131217408 |
| 13 | 1428028032 |
| 14 | 16709309440 |
| 15 | 210367491840 |
| 16 | 2847184825728 |