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 | -1 |
| 3 | 1 |
| 4 | -2 |
| 5 | 1 |
| 6 | 1 |
| 7 | -4 |
| 8 | 5 |
| 9 | -2 |
| 10 | 1 |
| 11 | -11 |
| 12 | 33 |
| 13 | -37 |
| 14 | 14 |
| 15 | 1 |
| 16 | -53 |
| 17 | 495 |
| 18 | -1423 |
| 19 | 1568 |
| 20 | -588 |
| 21 | 1 |
| 22 | -482 |
| 23 | 23232 |
| 24 | -213778 |
| 25 | 612035 |
| 26 | -673260 |
| 27 | 252252 |
| 28 | 1 |
| 29 | -7918 |
| 30 | 3607384 |
| 31 | -172966930 |
| 32 | 1590265243 |
| 33 | -4551765520 |
| 34 | 5006613612 |
| 35 | -1875745872 |
| 36 | 1 |
| 37 | -226266 |
| 38 | 1732486848 |
| 39 | -787838048562 |
| 40 | 37768573496883 |
| 41 | -347235787044084 |