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) |
|---|---|
| 5 | 1 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 251 |
| 11 | 922 |
| 12 | 1582 |
| 13 | 2572 |
| 14 | 4002 |
| 15 | 756755 |
| 16 | 6029297 |
| 17 | 31742676 |
| 18 | 120956707 |
| 19 | 398182782 |
| 20 | 12794989968 |
| 21 | 166170816448 |
| 22 | 1418774022895 |
| 23 | 9698826682676 |
| 24 | 55499002033421 |
| 25 | 894582818429967 |
| 26 | 14637215156295242 |
| 27 | 177486208140377619 |
| 28 | 1730337098015002802 |