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 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 420 |
| 8 | 154637 |
| 9 | 20368816 |
| 10 | 1775801814 |
| 11 | 124151410020 |
| 12 | 7596257673279 |
| 13 | 426319554841752 |
| 14 | 22564352299016528 |
| 15 | 1146221298547133380 |
| 16 | 56531610963314602401 |
| 17 | 2728475248127447671008 |
| 18 | 129586638359127411410442 |
| 19 | 6080467290450346517206500 |
| 20 | 282689089820505452872162403 |