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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 12 |
| 6 | 64 |
| 7 | 376 |
| 8 | 2557 |
| 9 | 19683 |
| 10 | 169350 |
| 11 | 1610592 |
| 12 | 16777216 |
| 13 | 189970982 |
| 14 | 2323244584 |
| 15 | 30517578125 |
| 16 | 428528437130 |
| 17 | 6405755132013 |
| 18 | 101559956668416 |
| 19 | 1702215647540101 |
| 20 | 30072865982171749 |
| 21 | 558545864083284007 |
| 22 | 10880062101736647492 |
| 23 | 221794805104450672070 |