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 | -1 |
| 4 | -1 |
| 5 | -1 |
| 6 | 0 |
| 7 | 4 |
| 8 | 15 |
| 9 | 40 |
| 10 | 86 |
| 11 | 134 |
| 12 | 16 |
| 13 | -1060 |
| 14 | -6119 |
| 15 | -25187 |
| 16 | -86678 |
| 17 | -250846 |
| 18 | -537819 |
| 19 | -175233 |
| 20 | 6998009 |
| 21 | 55632942 |
| 22 | 310923272 |
| 23 | 1465146781 |
| 24 | 6011047682 |
| 25 | 20719304348 |
| 26 | 49356093300 |
| 27 | -36579100806 |
| 28 | -1549214884054 |
| 29 | -13807417413199 |
| 30 | -92912464763743 |