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 | 16 |
| 3 | 48 |
| 4 | 256 |
| 5 | 800 |
| 6 | 3840 |
| 7 | 12544 |
| 8 | 65536 |
| 9 | 186624 |
| 10 | 986880 |
| 11 | 3345408 |
| 12 | 16515072 |
| 13 | 52306176 |
| 14 | 252645120 |
| 15 | 760320000 |
| 16 | 4288266240 |
| 17 | 13628740608 |
| 18 | 64258375680 |
| 19 | 218462552064 |
| 20 | 1095233372160 |
| 21 | 3105655160832 |
| 22 | 16510446886912 |
| 23 | 56000724240384 |
| 24 | 280012271910912 |
| 25 | 869940000000000 |