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 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 2 |
| 4 | -3 |
| 5 | 7 |
| 6 | -14 |
| 7 | 29 |
| 8 | -57 |
| 9 | 114 |
| 10 | -227 |
| 11 | 455 |
| 12 | -910 |
| 13 | 1821 |
| 14 | -3641 |
| 15 | 7282 |
| 16 | -14563 |
| 17 | 29127 |
| 18 | -58254 |
| 19 | 116509 |
| 20 | -233017 |
| 21 | 466034 |
| 22 | -932067 |
| 23 | 1864135 |
| 24 | -3728270 |
| 25 | 7456541 |
| 26 | -14913081 |
| 27 | 29826162 |
| 28 | -59652323 |
| 29 | 119304647 |
| 30 | -238609294 |
| 31 | 477218589 |
| 32 | -954437177 |
| 33 | 1908874354 |