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 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 20 |
| 5 | 277 |
| 6 | 5776 |
| 7 | 188900 |
| 8 | 9980698 |
| 9 | 868571406 |
| 10 | 125895356788 |
| 11 | 30578409431921 |
| 12 | 12487049992168856 |
| 13 | 8588968244025278785 |
| 14 | 9960996172657038782698 |
| 15 | 19489102605171036723471036 |
| 16 | 64349079323905130216144033784 |
| 17 | 358611512621756217468022899213127 |