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 | 1 |
| 2 | 0 |
| 3 | -1 |
| 4 | 3 |
| 5 | 0 |
| 6 | -3 |
| 7 | -3 |
| 8 | 9 |
| 9 | 0 |
| 10 | 150 |
| 11 | -9 |
| 12 | -9 |
| 13 | 27 |
| 14 | 0 |
| 15 | 1236 |
| 16 | 450 |
| 17 | -27 |
| 18 | -27 |
| 19 | 81 |
| 20 | 0 |
| 21 | -2555748 |
| 22 | 3708 |
| 23 | 1350 |
| 24 | -81 |
| 25 | -81 |
| 26 | 243 |
| 27 | 0 |
| 28 | -64342116 |
| 29 | -7667244 |
| 30 | 11124 |
| 31 | 4050 |
| 32 | -243 |
| 33 | -243 |
| 34 | 729 |
| 35 | 0 |
| 36 | 5885700899760 |
| 37 | -193026348 |
| 38 | -23001732 |
| 39 | 33372 |
| 40 | 12150 |
| 41 | -729 |
| 42 | -729 |
| 43 | 2187 |
| 44 | 0 |