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) |
|---|---|
| 2 | 2 |
| 3 | 3 |
| 4 | 5 |
| 5 | 23 |
| 6 | 239 |
| 7 | 719 |
| 8 | 5039 |
| 9 | 201599 |
| 10 | 1088639 |
| 11 | 14515199 |
| 12 | 159667199 |
| 13 | 479001599 |
| 14 | 31135103999 |
| 15 | 87178291199 |
| 16 | 2615348735999 |
| 17 | 188305108991999 |
| 18 | 711374856191999 |
| 19 | 192071211171839999 |
| 20 | 3649353012264959999 |
| 21 | 12164510040883199999 |
| 22 | 2248001455555215359999 |
| 23 | 2248001455555215359999 |