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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 0 |
| 4 | -5 |
| 5 | -3 |
| 6 | 35 |
| 7 | 11 |
| 8 | -65 |
| 9 | -3055 |
| 10 | 4433 |
| 11 | 2561 |
| 12 | -18863 |
| 13 | -614635 |
| 14 | 14705 |
| 15 | 3871801 |
| 16 | -6702403 |
| 17 | -23794993 |
| 18 | -21392575 |
| 19 | 1677354925 |
| 20 | 2206770805 |
| 21 | -30432904645 |
| 22 | -617315066615 |
| 23 | 2099373575975 |
| 24 | 551582580432325 |
| 25 | -11053607615333933 |
| 26 | -180184164588301 |
| 27 | 4198057769186443 |
| 28 | 435884809756010315 |