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 | 0 |
| 2 | 1 |
| 3 | 70 |
| 4 | 19355 |
| 5 | 11180820 |
| 6 | 11555272575 |
| 7 | 19506631814670 |
| 8 | 50262958713792825 |
| 9 | 187747837889699887800 |
| 10 | 976273961160363172131825 |
| 11 | 6840300875426184026353242750 |
| 12 | 62870315446244013091262178375075 |
| 13 | 741227949070136911068308523257857500 |