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 | -3 |
| 2 | 4 |
| 3 | -4 |
| 4 | 5 |
| 5 | -9 |
| 6 | 16 |
| 7 | -24 |
| 8 | 34 |
| 9 | -52 |
| 10 | 84 |
| 11 | -132 |
| 12 | 200 |
| 13 | -304 |
| 14 | 472 |
| 15 | -736 |
| 16 | 1136 |
| 17 | -1744 |
| 18 | 2688 |
| 19 | -4160 |
| 20 | 6432 |
| 21 | -9920 |
| 22 | 15296 |
| 23 | -23616 |
| 24 | 36480 |
| 25 | -56320 |
| 26 | 86912 |
| 27 | -134144 |
| 28 | 207104 |
| 29 | -319744 |
| 30 | 493568 |
| 31 | -761856 |
| 32 | 1176064 |
| 33 | -1815552 |
| 34 | 2802688 |
| 35 | -4326400 |
| 36 | 6678528 |
| 37 | -10309632 |
| 38 | 15915008 |