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 | 2 |
| 2 | 4 |
| 3 | 16 |
| 4 | 48 |
| 5 | 160 |
| 6 | 512 |
| 7 | 1664 |
| 8 | 5376 |
| 9 | 17408 |
| 10 | 56320 |
| 11 | 182272 |
| 12 | 589824 |
| 13 | 1908736 |
| 14 | 6176768 |
| 15 | 19988480 |
| 16 | 64684032 |
| 17 | 209321984 |
| 18 | 677380096 |
| 19 | 2192048128 |
| 20 | 7093616640 |
| 21 | 22955425792 |
| 22 | 74285318144 |
| 23 | 240392339456 |
| 24 | 777925951488 |
| 25 | 2517421260800 |