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 | 0 |
| 3 | -1 |
| 4 | -2 |
| 5 | -2 |
| 6 | 2 |
| 7 | 17 |
| 8 | 54 |
| 9 | 109 |
| 10 | 54 |
| 11 | -796 |
| 12 | -5000 |
| 13 | -19499 |
| 14 | -52252 |
| 15 | -44617 |
| 16 | 577554 |
| 17 | 5071906 |
| 18 | 27330978 |
| 19 | 108557573 |
| 20 | 263947354 |
| 21 | -453137963 |
| 22 | -11252508862 |
| 23 | -92193933208 |
| 24 | -545809325184 |
| 25 | -2441788385255 |
| 26 | -6271647457176 |
| 27 | 22814756330975 |
| 28 | 492197181810550 |
| 29 | 4609129908957190 |