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 | 28 |
| 3 | 1638 |
| 4 | 6200 |
| 5 | 950976 |
| 6 | 2178540 |
| 7 | 2457000 |
| 8 | 4713984 |
| 9 | 45532800 |
| 10 | 142990848 |
| 11 | 459818240 |
| 12 | 1381161600 |
| 13 | 10200236032 |
| 14 | 57575890944 |
| 15 | 109585986048 |
| 16 | 513480135168 |
| 17 | 1553357978368 |
| 18 | 10881843388416 |
| 19 | 43947421401888 |