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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 34 |
| 4 | 460 |
| 5 | 8608 |
| 6 | 206152 |
| 7 | 6020992 |
| 8 | 207574240 |
| 9 | 8251015264 |
| 10 | 371527296256 |
| 11 | 18691127602816 |
| 12 | 1039066330203520 |
| 13 | 63253339835514112 |
| 14 | 4184830238170091008 |
| 15 | 298985971407749744128 |
| 16 | 22941517126450315985920 |
| 17 | 1881603821848104123344896 |
| 18 | 164271703613261014954276864 |