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 | 0 |
| 3 | 18 |
| 4 | 240 |
| 5 | 3100 |
| 6 | 46620 |
| 7 | 823494 |
| 8 | 16777152 |
| 9 | 387420408 |
| 10 | 9999999900 |
| 11 | 285311670490 |
| 12 | 8916100448112 |
| 13 | 302875106592084 |
| 14 | 11112006825557820 |
| 15 | 437893890380859150 |
| 16 | 18446744073709551360 |