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 | 0 |
| 4 | -4 |
| 5 | 0 |
| 6 | -24 |
| 7 | -32 |
| 8 | -120 |
| 9 | -336 |
| 10 | -768 |
| 11 | -2496 |
| 12 | -6612 |
| 13 | -17296 |
| 14 | -61176 |
| 15 | -150016 |
| 16 | -518308 |
| 17 | -1418576 |
| 18 | -4266064 |
| 19 | -12800864 |
| 20 | -36773692 |
| 21 | -112996720 |
| 22 | -334128168 |
| 23 | -1009728992 |
| 24 | -3068945888 |
| 25 | -9160795472 |
| 26 | -27959064832 |