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 | 3 |
| 4 | 34 |
| 5 | 91 |
| 6 | 1430 |
| 7 | 12441 |
| 8 | 125970 |
| 9 | 3095547 |
| 10 | 67083870 |
| 11 | 1560337779 |
| 12 | 42483256530 |
| 13 | 1278362451795 |
| 14 | 50174604862382 |
| 15 | 3146934482482791 |
| 16 | 109416477603465890 |
| 17 | 4497598794363331965 |
| 18 | 327313882010942897070 |
| 19 | 14916466618879283766165 |