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 | -2 |
| 2 | 2 |
| 3 | -2 |
| 4 | 4 |
| 5 | -8 |
| 6 | 12 |
| 7 | -16 |
| 8 | 24 |
| 9 | -40 |
| 10 | 64 |
| 11 | -96 |
| 12 | 144 |
| 13 | -224 |
| 14 | 352 |
| 15 | -544 |
| 16 | 832 |
| 17 | -1280 |
| 18 | 1984 |
| 19 | -3072 |
| 20 | 4736 |
| 21 | -7296 |
| 22 | 11264 |
| 23 | -17408 |
| 24 | 26880 |
| 25 | -41472 |
| 26 | 64000 |
| 27 | -98816 |
| 28 | 152576 |
| 29 | -235520 |
| 30 | 363520 |
| 31 | -561152 |
| 32 | 866304 |
| 33 | -1337344 |
| 34 | 2064384 |
| 35 | -3186688 |
| 36 | 4919296 |
| 37 | -7593984 |
| 38 | 11722752 |
| 39 | -18096128 |
| 40 | 27934720 |
| 41 | -43122688 |