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 | -7 |
| 2 | 28 |
| 3 | -84 |
| 4 | 210 |
| 5 | -462 |
| 6 | 924 |
| 7 | -1715 |
| 8 | 2989 |
| 9 | -4900 |
| 10 | 7448 |
| 11 | -9996 |
| 12 | 9996 |
| 13 | 0 |
| 14 | -38759 |
| 15 | 149205 |
| 16 | -422576 |
| 17 | 1041348 |
| 18 | -2350922 |
| 19 | 4970070 |
| 20 | -9940140 |
| 21 | 18874261 |
| 22 | -33957343 |
| 23 | 57374296 |
| 24 | -89125120 |
| 25 | 120875944 |
| 26 | -120875944 |
| 27 | 0 |
| 28 | 459957169 |
| 29 | -1749692735 |
| 30 | 4904887652 |