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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | -11 |
| 5 | -45 |
| 6 | -119 |
| 7 | -49 |
| 8 | 2045 |
| 9 | 18075 |
| 10 | 105121 |
| 11 | 436471 |
| 12 | 679669 |
| 13 | -10538333 |
| 14 | -155858247 |
| 15 | -1404609569 |
| 16 | -9667430739 |
| 17 | -46708291093 |
| 18 | -25694453615 |
| 19 | 3002522206471 |
| 20 | 49051481154341 |
| 21 | 546022210068595 |
| 22 | 4800733688293929 |
| 23 | 31399017314213487 |
| 24 | 75507020603213405 |