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 | -4 |
| 2 | 12 |
| 3 | -20 |
| 4 | -20 |
| 5 | 172 |
| 6 | 108 |
| 7 | -2388 |
| 8 | -3220 |
| 9 | 47532 |
| 10 | 161900 |
| 11 | -1062740 |
| 12 | -8532628 |
| 13 | 13623212 |
| 14 | 431041132 |
| 15 | 1206169260 |
| 16 | -17833021588 |
| 17 | -169685043796 |
| 18 | 180187176044 |
| 19 | 13462762665132 |
| 20 | 79377664422252 |
| 21 | -553096696140884 |
| 22 | -11670986989785492 |
| 23 | -44371854928405844 |
| 24 | 829755609457185644 |