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 | -30 |
| 2 | 390 |
| 3 | -2860 |
| 4 | 12870 |
| 5 | -36036 |
| 6 | 60060 |
| 7 | -51480 |
| 8 | 12870 |
| 9 | 2860 |
| 10 | 1716 |
| 11 | 1560 |
| 12 | 1820 |
| 13 | 2520 |
| 14 | 3960 |
| 15 | 6864 |
| 16 | 12870 |
| 17 | 25740 |
| 18 | 54340 |
| 19 | 120120 |
| 20 | 276276 |
| 21 | 657800 |
| 22 | 1614600 |
| 23 | 4071600 |
| 24 | 10518300 |
| 25 | 27768312 |
| 26 | 74760840 |
| 27 | 204900080 |
| 28 | 570793080 |
| 29 | 1613966640 |
| 30 | 4626704368 |
| 31 | 13432367520 |