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 | -1 |
| 2 | 1 |
| 3 | -1 |
| 4 | 2 |
| 5 | -3 |
| 6 | 4 |
| 7 | -6 |
| 8 | 9 |
| 9 | -13 |
| 10 | 19 |
| 11 | -28 |
| 12 | 41 |
| 13 | -61 |
| 14 | 90 |
| 15 | -132 |
| 16 | 195 |
| 17 | -288 |
| 18 | 424 |
| 19 | -625 |
| 20 | 922 |
| 21 | -1359 |
| 22 | 2004 |
| 23 | -2955 |
| 24 | 4356 |
| 25 | -6423 |
| 26 | 9471 |
| 27 | -13963 |
| 28 | 20587 |
| 29 | -30355 |
| 30 | 44755 |
| 31 | -65987 |
| 32 | 97293 |
| 33 | -143449 |
| 34 | 211503 |
| 35 | -311844 |
| 36 | 459785 |
| 37 | -677912 |
| 38 | 999524 |
| 39 | -1473709 |
| 40 | 2172854 |
| 41 | -3203685 |
| 42 | 4723551 |
| 43 | -6964461 |
| 44 | 10268490 |
| 45 | -15139986 |