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 | 1 |
| 3 | 0 |
| 4 | -5 |
| 5 | -22 |
| 6 | -68 |
| 7 | -165 |
| 8 | -285 |
| 9 | -96 |
| 10 | 1892 |
| 11 | 10574 |
| 12 | 38436 |
| 13 | 107175 |
| 14 | 217063 |
| 15 | 165232 |
| 16 | -1150565 |
| 17 | -7780744 |
| 18 | -31173680 |
| 19 | -94537100 |
| 20 | -212903852 |
| 21 | -239418048 |
| 22 | 788015576 |
| 23 | 6734057510 |
| 24 | 29396759220 |
| 25 | 95418332383 |
| 26 | 233697161887 |
| 27 | 334222633632 |
| 28 | -514863450175 |
| 29 | -6299672869750 |