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 | 10 |
| 4 | 34 |
| 5 | 218 |
| 6 | 1308 |
| 7 | 10596 |
| 8 | 74688 |
| 9 | 793152 |
| 10 | 7931520 |
| 11 | 94504320 |
| 12 | 1054218240 |
| 13 | 14662840320 |
| 14 | 205279764480 |
| 15 | 3427909632000 |
| 16 | 50923531008000 |
| 17 | 907545606912000 |
| 18 | 16335820924416000 |
| 19 | 323185344975360000 |
| 20 | 6220416698689536000 |
| 21 | 140360358705186816000 |
| 22 | 3087927891514109952000 |