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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 7 |
| 5 | 381 |
| 6 | 21748 |
| 7 | 1781154 |
| 8 | 249849880 |
| 9 | 66257728763 |
| 10 | 34495508486976 |
| 11 | 35641629989151608 |
| 12 | 73354595357480683904 |
| 13 | 301272202621204113362497 |
| 14 | 2471648811029413368450098688 |
| 15 | 40527680937730440155535277704046 |
| 16 | 1328578958335783199341353852258282496 |