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 | 4 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | -6 |
| 7 | 14 |
| 8 | -25 |
| 9 | 32 |
| 10 | 6 |
| 11 | -250 |
| 12 | 1222 |
| 13 | -4380 |
| 14 | 13059 |
| 15 | -31705 |
| 16 | 48464 |
| 17 | 76354 |
| 18 | -1159911 |
| 19 | 7041015 |
| 20 | -33400183 |
| 21 | 135931668 |
| 22 | -473704510 |
| 23 | 1277600695 |
| 24 | -1233828142 |
| 25 | -16196871172 |
| 26 | 169736941512 |
| 27 | -1156974034428 |
| 28 | 6577630531262 |
| 29 | -32839667759307 |
| 30 | 142900400342885 |