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 | 0 |
| 5 | -1 |
| 6 | 3 |
| 7 | -5 |
| 8 | 7 |
| 9 | -8 |
| 10 | 1 |
| 11 | 24 |
| 12 | -62 |
| 13 | 82 |
| 14 | -60 |
| 15 | 52 |
| 16 | -242 |
| 17 | 877 |
| 18 | -1979 |
| 19 | 2747 |
| 20 | -924 |
| 21 | -7309 |
| 22 | 28389 |
| 23 | -79469 |
| 24 | 205108 |
| 25 | -468281 |
| 26 | 821680 |
| 27 | -772531 |
| 28 | -1046280 |
| 29 | 6962678 |
| 30 | -19516746 |
| 31 | 39741239 |
| 32 | -63920180 |
| 33 | 75119743 |
| 34 | -21689924 |
| 35 | -219360085 |
| 36 | 866264658 |
| 37 | -2165202646 |
| 38 | 4125523796 |
| 39 | -6023253532 |