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 | -2 |
| 2 | 2 |
| 3 | 0 |
| 4 | -6 |
| 5 | 20 |
| 6 | -48 |
| 7 | 96 |
| 8 | -166 |
| 9 | 252 |
| 10 | -340 |
| 11 | 416 |
| 12 | -480 |
| 13 | 544 |
| 14 | -544 |
| 15 | 0 |
| 16 | 2906 |
| 17 | -13396 |
| 18 | 44100 |
| 19 | -121792 |
| 20 | 296860 |
| 21 | -652808 |
| 22 | 1306560 |
| 23 | -2377280 |
| 24 | 3879136 |
| 25 | -5461952 |
| 26 | 5892512 |
| 27 | -2171520 |
| 28 | -11699616 |
| 29 | 45871040 |
| 30 | -114213888 |
| 31 | 228427776 |
| 32 | -377994406 |
| 33 | 478195212 |
| 34 | -252252460 |
| 35 | -1013309824 |