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 | 1 |
| 3 | 6 |
| 4 | 32 |
| 5 | 160 |
| 6 | 784 |
| 7 | 3808 |
| 8 | 18432 |
| 9 | 89088 |
| 10 | 430336 |
| 11 | 2078208 |
| 12 | 10035200 |
| 13 | 48455680 |
| 14 | 233967616 |
| 15 | 1129701376 |
| 16 | 5454692352 |
| 17 | 26337607680 |
| 18 | 127169265664 |
| 19 | 614027624448 |
| 20 | 2964787822592 |
| 21 | 14315262312448 |
| 22 | 69120201588736 |