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 | 0 |
| 2 | 0 |
| 3 | -2 |
| 4 | 0 |
| 5 | -12 |
| 6 | 14 |
| 7 | -90 |
| 8 | 192 |
| 9 | -792 |
| 10 | 2148 |
| 11 | -7716 |
| 12 | 23262 |
| 13 | -79512 |
| 14 | 252054 |
| 15 | -846628 |
| 16 | 2753520 |
| 17 | -9205800 |
| 18 | 30371124 |
| 19 | -101585544 |
| 20 | 338095596 |
| 21 | -1133491188 |
| 22 | 3794908752 |
| 23 | -12758932158 |
| 24 | 42903505030 |
| 25 | -144655483440 |
| 26 | 488092130664 |
| 27 | -1650000819068 |
| 28 | 5583090702798 |
| 29 | -18918470423736 |
| 30 | 64167341172984 |
| 31 | -217893807812346 |
| 32 | 740578734923544 |