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 | 1 |
| 1 | 4 |
| 2 | 32 |
| 3 | 336 |
| 4 | 4096 |
| 5 | 54912 |
| 6 | 786432 |
| 7 | 11824384 |
| 8 | 184549376 |
| 9 | 2966845440 |
| 10 | 48855252992 |
| 11 | 820675092480 |
| 12 | 14018773254144 |
| 13 | 242919827374080 |
| 14 | 4261707069259776 |
| 15 | 75576645116559360 |
| 16 | 1353050213048123392 |
| 17 | 24428493151359467520 |
| 18 | 444370175232646840320 |
| 19 | 8138178004138611179520 |