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 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 22 |
| 6 | 48 |
| 7 | 156 |
| 8 | 320 |
| 9 | 1008 |
| 10 | 2640 |
| 11 | 7700 |
| 12 | 13824 |
| 13 | 61320 |
| 14 | 170352 |
| 15 | 401280 |
| 16 | 983040 |
| 17 | 3796100 |
| 18 | 7838208 |
| 19 | 30566592 |
| 20 | 62304000 |
| 21 | 229686912 |
| 22 | 670824000 |
| 23 | 2003046356 |
| 24 | 3583180800 |
| 25 | 15403487000 |
| 26 | 48881851200 |
| 27 | 128672022528 |
| 28 | 314657860608 |
| 29 | 1163185915872 |
| 30 | 2340264960000 |
| 31 | 9947788640064 |