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 | -2 |
| 3 | 5 |
| 4 | -9 |
| 5 | 14 |
| 6 | -24 |
| 7 | 47 |
| 8 | -87 |
| 9 | 151 |
| 10 | -272 |
| 11 | 505 |
| 12 | -918 |
| 13 | 1656 |
| 14 | -3020 |
| 15 | 5512 |
| 16 | -10020 |
| 17 | 18221 |
| 18 | -33172 |
| 19 | 60388 |
| 20 | -109899 |
| 21 | 199992 |
| 22 | -364002 |
| 23 | 662529 |
| 24 | -1205777 |
| 25 | 2194488 |
| 26 | -3994057 |
| 27 | 7269275 |
| 28 | -13230124 |
| 29 | 24078998 |
| 30 | -43824226 |
| 31 | 79760817 |
| 32 | -145165804 |
| 33 | 264203948 |
| 34 | -480855437 |
| 35 | 875164374 |