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 | 15 |
| 3 | -35 |
| 4 | 70 |
| 5 | -124 |
| 6 | 190 |
| 7 | -220 |
| 8 | 55 |
| 9 | 715 |
| 10 | -2999 |
| 11 | 8585 |
| 12 | -20580 |
| 13 | 43520 |
| 14 | -81940 |
| 15 | 134376 |
| 16 | -176195 |
| 17 | 118435 |
| 18 | 279235 |
| 19 | -1572395 |
| 20 | 4900626 |
| 21 | -12339900 |
| 22 | 27139450 |
| 23 | -53163300 |
| 24 | 91745475 |
| 25 | -131888749 |
| 26 | 125584845 |
| 27 | 66464465 |
| 28 | -781173960 |
| 29 | 2736565920 |
| 30 | -7295547624 |
| 31 | 16717081040 |