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 | 10 |
| 3 | 82 |
| 4 | 640 |
| 5 | 4924 |
| 6 | 37720 |
| 7 | 288568 |
| 8 | 2206720 |
| 9 | 16872976 |
| 10 | 129008800 |
| 11 | 986374432 |
| 12 | 7541585920 |
| 13 | 57661119424 |
| 14 | 440862647680 |
| 15 | 3370726327168 |
| 16 | 25771735613440 |
| 17 | 197044282245376 |
| 18 | 1506551581411840 |
| 19 | 11518718733701632 |
| 20 | 88069258871603200 |