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 | 2 |
| 3 | -1 |
| 4 | -11 |
| 5 | 19 |
| 6 | 201 |
| 7 | -764 |
| 8 | -7426 |
| 9 | 52137 |
| 10 | 448435 |
| 11 | -5377604 |
| 12 | -38712486 |
| 13 | 777663613 |
| 14 | 4258812299 |
| 15 | -149524753650 |
| 16 | -505685566184 |
| 17 | 36733876797025 |
| 18 | 30910872539763 |
| 19 | -11174584391207360 |
| 20 | 25170998506744790 |
| 21 | 4101787001153848461 |
| 22 | -24862093152821214653 |
| 23 | -1776483826032814964966 |