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 | 4 |
| 4 | 9 |
| 5 | 76 |
| 6 | 175 |
| 7 | 3606 |
| 8 | 833 |
| 9 | 354376 |
| 10 | -1605249 |
| 11 | 65111410 |
| 12 | -718371071 |
| 13 | 20105327100 |
| 14 | -351241054177 |
| 15 | 9362931464446 |
| 16 | -214514949732735 |
| 17 | 6039303900168976 |
| 18 | -165679758877120001 |
| 19 | 5093296357218337386 |
| 20 | -159900268661169533119 |
| 21 | 5405435526807425433220 |