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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 6 |
| 5 | 2116 |
| 6 | 291966 |
| 7 | 23312156 |
| 8 | 1362515742 |
| 9 | 65691305652 |
| 10 | 2792020643502 |
| 11 | 108871903828732 |
| 12 | 3995501812110798 |
| 13 | 140371634250355508 |
| 14 | 4776934559777356158 |
| 15 | 158783001150185585628 |
| 16 | 5186356918189216064574 |
| 17 | 167203226479257200020084 |
| 18 | 5337930997910228958536334 |