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 | 7 |
| 4 | 11 |
| 5 | 121 |
| 6 | 479 |
| 7 | 5041 |
| 8 | 18479 |
| 9 | 423361 |
| 10 | 1844639 |
| 11 | 39916801 |
| 12 | 298710719 |
| 13 | 6227020801 |
| 14 | 43606442879 |
| 15 | 1536517382401 |
| 16 | 9589093113599 |
| 17 | 355687428096001 |
| 18 | 4259374594675199 |
| 19 | 121645100408832001 |
| 20 | 1135353600039859199 |