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 | 3 |
| 3 | 12 |
| 4 | 260 |
| 5 | 5720 |
| 6 | 314248 |
| 7 | 17255072 |
| 8 | 1769058016 |
| 9 | 181357735680 |
| 10 | 29880655637760 |
| 11 | 4923158441956352 |
| 12 | 1189676108826729472 |
| 13 | 287484053261423565824 |
| 14 | 95784714773484796761088 |
| 15 | 31913810779214031287095296 |
| 16 | 2804341960426298188743438336 |
| 17 | 1232120770958699233546743119872 |