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 | 4 |
| 3 | 8 |
| 4 | 64 |
| 5 | 640 |
| 6 | 2560 |
| 7 | 35840 |
| 8 | 114688 |
| 9 | 688128 |
| 10 | 13762560 |
| 11 | 14417920 |
| 12 | 346030080 |
| 13 | 1799356416 |
| 14 | 2399141888 |
| 15 | 23991418880 |
| 16 | 767725404160 |
| 17 | 2372969431040 |
| 18 | 5695126634496 |
| 19 | 216414812110848 |
| 20 | 221963909857280 |
| 21 | 9322484214005760 |