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 | 5 |
| 5 | -7 |
| 6 | 13 |
| 7 | -23 |
| 8 | 37 |
| 9 | -63 |
| 10 | 109 |
| 11 | -183 |
| 12 | 309 |
| 13 | -527 |
| 14 | 893 |
| 15 | -1511 |
| 16 | 2565 |
| 17 | -4351 |
| 18 | 7373 |
| 19 | -12503 |
| 20 | 21205 |
| 21 | -35951 |
| 22 | 60957 |
| 23 | -103367 |
| 24 | 175269 |
| 25 | -297183 |
| 26 | 503917 |
| 27 | -854455 |
| 28 | 1448821 |
| 29 | -2456655 |
| 30 | 4165565 |
| 31 | -7063207 |
| 32 | 11976517 |
| 33 | -20307647 |
| 34 | 34434061 |
| 35 | -58387095 |
| 36 | 99002389 |
| 37 | -167870511 |
| 38 | 284644701 |