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 | 7 |
| 2 | 32 |
| 3 | 120 |
| 4 | 400 |
| 5 | 1232 |
| 6 | 3584 |
| 7 | 9984 |
| 8 | 26880 |
| 9 | 70400 |
| 10 | 180224 |
| 11 | 452608 |
| 12 | 1118208 |
| 13 | 2723840 |
| 14 | 6553600 |
| 15 | 15597568 |
| 16 | 36765696 |
| 17 | 85917696 |
| 18 | 199229440 |
| 19 | 458752000 |
| 20 | 1049624576 |
| 21 | 2387607552 |
| 22 | 5402263552 |
| 23 | 12163481600 |
| 24 | 27262976000 |
| 25 | 60850962432 |