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) |
|---|---|
| 5 | 23 |
| 6 | 143 |
| 7 | 1007 |
| 8 | 8063 |
| 9 | 72575 |
| 10 | 725759 |
| 11 | 7983359 |
| 12 | 95800319 |
| 13 | 1245404159 |
| 14 | 17435658239 |
| 15 | 261534873599 |
| 16 | 4184557977599 |
| 17 | 71137485619199 |
| 18 | 1280474741145599 |
| 19 | 24329020081766399 |
| 20 | 486580401635327999 |