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 | -30 |
| 4 | 40 |
| 5 | -25 |
| 6 | -35 |
| 7 | 140 |
| 8 | -250 |
| 9 | 285 |
| 10 | -150 |
| 11 | -210 |
| 12 | 740 |
| 13 | -1230 |
| 14 | 1330 |
| 15 | -675 |
| 16 | -880 |
| 17 | 3015 |
| 18 | -4830 |
| 19 | 5025 |
| 20 | -2450 |
| 21 | -3135 |
| 22 | 10380 |
| 23 | -16180 |
| 24 | 16450 |
| 25 | -7875 |
| 26 | -9785 |
| 27 | 31850 |
| 28 | -48720 |
| 29 | 48600 |
| 30 | -22800 |
| 31 | -27985 |
| 32 | 89465 |
| 33 | -134760 |
| 34 | 132530 |
| 35 | -61400 |
| 36 | -74205 |
| 37 | 234515 |
| 38 | -349000 |
| 39 | 339145 |