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 | -3 |
| 4 | 3 |
| 5 | -5 |
| 6 | 9 |
| 7 | -11 |
| 8 | 19 |
| 9 | -29 |
| 10 | 41 |
| 11 | -67 |
| 12 | 99 |
| 13 | -149 |
| 14 | 233 |
| 15 | -347 |
| 16 | 531 |
| 17 | -813 |
| 18 | 1225 |
| 19 | -1875 |
| 20 | 2851 |
| 21 | -4325 |
| 22 | 6601 |
| 23 | -10027 |
| 24 | 15251 |
| 25 | -23229 |
| 26 | 35305 |
| 27 | -53731 |
| 28 | 81763 |
| 29 | -124341 |
| 30 | 189225 |
| 31 | -287867 |
| 32 | 437907 |
| 33 | -666317 |
| 34 | 1013641 |
| 35 | -1542131 |
| 36 | 2346275 |
| 37 | -3569413 |
| 38 | 5430537 |
| 39 | -8261963 |
| 40 | 12569363 |
| 41 | -19123037 |
| 42 | 29093289 |