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 | 1 |
| 3 | 1 |
| 4 | 17 |
| 5 | 337 |
| 6 | 6641 |
| 7 | 130865 |
| 8 | 2578785 |
| 9 | 50816737 |
| 10 | 1001378849 |
| 11 | 19732860833 |
| 12 | 388849631729 |
| 13 | 7662550168241 |
| 14 | 150995835638929 |
| 15 | 2975477077435217 |
| 16 | 58633827885912001 |
| 17 | 1155420016046016193 |
| 18 | 22768348266078953793 |