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 | -1 |
| 3 | 3 |
| 4 | 27 |
| 5 | -89 |
| 6 | -1057 |
| 7 | 48771 |
| 8 | -178481 |
| 9 | 9099507 |
| 10 | 128207979 |
| 11 | -483939977 |
| 12 | -6958934353 |
| 13 | 26494256091 |
| 14 | -21862134113449 |
| 15 | 84179432287299 |
| 16 | -72624976668147841 |
| 17 | 281629680514649643 |
| 18 | 4246732448623781667 |
| 19 | -250191601741438157017 |
| 20 | 14833445639443302757131 |
| 21 | -57912614113275649087721 |
| 22 | 3457933070629553840500347 |
| 23 | -207403566791267899459539137 |
| 24 | -3185051759367410556524379913 |