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 | -5 |
| 2 | 5 |
| 3 | 20 |
| 4 | -45 |
| 5 | -25 |
| 6 | -80 |
| 7 | 390 |
| 8 | 525 |
| 9 | -1190 |
| 10 | 275 |
| 11 | -5340 |
| 12 | 4320 |
| 13 | 13980 |
| 14 | -11310 |
| 15 | 6100 |
| 16 | -54285 |
| 17 | 127760 |
| 18 | 90440 |
| 19 | -418100 |
| 20 | -101475 |
| 21 | -656760 |
| 22 | 1062660 |
| 23 | 3152270 |
| 24 | -2318400 |
| 25 | -375125 |
| 26 | -7283580 |
| 27 | 19641800 |
| 28 | 28602990 |
| 29 | -77134350 |
| 30 | -8320400 |
| 31 | -215403040 |
| 32 | 228722445 |
| 33 | 422949360 |