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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 15 |
| 7 | 35 |
| 8 | 70 |
| 9 | 125 |
| 10 | 200 |
| 11 | 275 |
| 12 | 275 |
| 13 | 0 |
| 14 | -1000 |
| 15 | -3625 |
| 16 | -9500 |
| 17 | -21250 |
| 18 | -42500 |
| 19 | -76875 |
| 20 | -124375 |
| 21 | -171875 |
| 22 | -171875 |
| 23 | 0 |
| 24 | 621875 |
| 25 | 2250000 |
| 26 | 5890625 |
| 27 | 13171875 |
| 28 | 26343750 |
| 29 | 47656250 |
| 30 | 77109375 |
| 31 | 106562500 |
| 32 | 106562500 |
| 33 | 0 |
| 34 | -385546875 |
| 35 | -1394921875 |
| 36 | -3651953125 |