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 | -10 |
| 2 | 35 |
| 3 | -50 |
| 4 | 25 |
| 5 | -2 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | -1 |
| 11 | -10 |
| 12 | -65 |
| 13 | -350 |
| 14 | -1700 |
| 15 | -7752 |
| 16 | -33915 |
| 17 | -144210 |
| 18 | -600875 |
| 19 | -2466750 |
| 20 | -10015005 |
| 21 | -40320150 |
| 22 | -161280600 |
| 23 | -641886000 |
| 24 | -2544619500 |
| 25 | -10056336264 |
| 26 | -39645171810 |
| 27 | -155989499540 |
| 28 | -612815891050 |
| 29 | -2404551645100 |
| 30 | -9425842448792 |