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 | 6 |
| 4 | 12 |
| 5 | 147 |
| 6 | 441 |
| 7 | 8112 |
| 8 | 32448 |
| 9 | 796005 |
| 10 | 3980025 |
| 11 | 122054688 |
| 12 | 732328128 |
| 13 | 26950548807 |
| 14 | 188653841649 |
| 15 | 8099902347264 |
| 16 | 64799218778112 |
| 17 | 3179644775178921 |
| 18 | 28616802976610289 |
| 19 | 1579734079664832000 |
| 20 | 15797340796648320000 |