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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -1 |
| 5 | 3 |
| 6 | -6 |
| 7 | 10 |
| 8 | -14 |
| 9 | 15 |
| 10 | -7 |
| 11 | -20 |
| 12 | 80 |
| 13 | -188 |
| 14 | 351 |
| 15 | -549 |
| 16 | 702 |
| 17 | -622 |
| 18 | -42 |
| 19 | 1839 |
| 20 | -5471 |
| 21 | 11560 |
| 22 | -20064 |
| 23 | 29144 |
| 24 | -33329 |
| 25 | 21059 |
| 26 | 27730 |
| 27 | -142182 |
| 28 | 355626 |
| 29 | -689121 |
| 30 | 1114937 |
| 31 | -1490892 |
| 32 | 1461360 |
| 33 | -337220 |
| 34 | -2996465 |
| 35 | 10030587 |
| 36 | -22226506 |
| 37 | 39921442 |
| 38 | -60118930 |
| 39 | 72788383 |
| 40 | -55703295 |
| 41 | -31057776 |