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 | 9 |
| 2 | 54 |
| 3 | 243 |
| 4 | 810 |
| 5 | 1701 |
| 6 | 0 |
| 7 | -16038 |
| 8 | -56862 |
| 9 | 0 |
| 10 | 817938 |
| 11 | 3241134 |
| 12 | 0 |
| 13 | -53872371 |
| 14 | -224386200 |
| 15 | 0 |
| 16 | 4017339666 |
| 17 | 17216031195 |
| 18 | 0 |
| 19 | -322568743770 |
| 20 | -1408090130370 |
| 21 | 0 |
| 22 | 27206369474544 |
| 23 | 120309415164990 |
| 24 | 0 |
| 25 | -2376712950727284 |
| 26 | -10611290417552118 |
| 27 | 0 |
| 28 | 213172869272924088 |