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 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 51 |
| 4 | 807 |
| 5 | 17445 |
| 6 | 479565 |
| 7 | 16019955 |
| 8 | 630301455 |
| 9 | 28552506885 |
| 10 | 1463744449125 |
| 11 | 83780913568275 |
| 12 | 5296205435649975 |
| 13 | 366478026602012325 |
| 14 | 27552067849812030525 |
| 15 | 2236327624673777509875 |
| 16 | 194908916445067162713375 |
| 17 | 18154937081288124469477125 |
| 18 | 1799824448875247911270279125 |