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 | 2 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 48 |
| 6 | 160 |
| 7 | 636 |
| 8 | 3556 |
| 9 | 19488 |
| 10 | 95872 |
| 11 | 594320 |
| 12 | 4459888 |
| 13 | 32131648 |
| 14 | 227072544 |
| 15 | 1875064880 |
| 16 | 17851780784 |
| 17 | 165367171136 |
| 18 | 1506506453568 |
| 19 | 15540217445728 |
| 20 | 179708231523680 |
| 21 | 2034547787823488 |
| 22 | 22716589497430656 |