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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 840 |
| 5 | 15824 |
| 6 | 112680 |
| 7 | 516160 |
| 8 | 1778608 |
| 9 | 5082912 |
| 10 | 12622640 |
| 11 | 28225472 |
| 12 | 58013112 |
| 13 | 111476080 |
| 14 | 202472856 |
| 15 | 350897664 |
| 16 | 584067552 |
| 17 | 939135552 |
| 18 | 1464903648 |
| 19 | 2225144448 |
| 20 | 3300867240 |
| 21 | 4794722064 |
| 22 | 6833735304 |
| 23 | 9574980800 |
| 24 | 13208790672 |