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 | -2 |
| 2 | 1 |
| 3 | -7 |
| 4 | 16 |
| 5 | -28 |
| 6 | 62 |
| 7 | -118 |
| 8 | 303 |
| 9 | -630 |
| 10 | 1152 |
| 11 | -2426 |
| 12 | 5315 |
| 13 | -10718 |
| 14 | 20482 |
| 15 | -43449 |
| 16 | 91111 |
| 17 | -179254 |
| 18 | 358910 |
| 19 | -727829 |
| 20 | 1484601 |
| 21 | -2995681 |
| 22 | 5924606 |
| 23 | -11935441 |
| 24 | 24382120 |
| 25 | -48702245 |
| 26 | 96682698 |
| 27 | -195063604 |
| 28 | 392983826 |
| 29 | -784903199 |
| 30 | 1569490057 |
| 31 | -3146479152 |
| 32 | 6317124649 |
| 33 | -12652202092 |