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) |
|---|---|
| 4 | -15 |
| 5 | -48 |
| 6 | 2024 |
| 7 | 31616 |
| 8 | 274480 |
| 9 | 1784320 |
| 10 | 9645312 |
| 11 | 45735936 |
| 12 | 196441344 |
| 13 | 780595200 |
| 14 | 2912532480 |
| 15 | 10315202560 |
| 16 | 34963222528 |
| 17 | 114140905472 |
| 18 | 360716042240 |
| 19 | 1108051230720 |
| 20 | 3319564664832 |
| 21 | 9726122262528 |
| 22 | 27935264735232 |
| 23 | 78810426900480 |
| 24 | 218761889054720 |
| 25 | 598349308755968 |