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 | 0 |
| 3 | 6 |
| 4 | 50 |
| 5 | 1220 |
| 6 | 42122 |
| 7 | 2278248 |
| 8 | 182111666 |
| 9 | 21094774212 |
| 10 | 3479970392642 |
| 11 | 807001730170592 |
| 12 | 260359119927269882 |
| 13 | 115887302333840512956 |
| 14 | 70677462143507496419690 |
| 15 | 58725460618979611312258632 |