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 | 1 |
| 4 | -1 |
| 5 | 0 |
| 6 | 1 |
| 7 | -1 |
| 8 | -1 |
| 9 | 0 |
| 10 | 1 |
| 11 | -1 |
| 12 | -3 |
| 13 | -3 |
| 14 | 0 |
| 15 | 1 |
| 16 | -1 |
| 17 | -7 |
| 18 | -29 |
| 19 | -13 |
| 20 | 0 |
| 21 | 1 |
| 22 | -1 |
| 23 | -15 |
| 24 | -201 |
| 25 | -499 |
| 26 | -71 |
| 27 | 0 |
| 28 | 1 |
| 29 | -1 |
| 30 | -31 |
| 31 | -1265 |
| 32 | -13351 |
| 33 | -13101 |
| 34 | -461 |
| 35 | 0 |
| 36 | 1 |
| 37 | -1 |
| 38 | -63 |
| 39 | -7713 |
| 40 | -328975 |
| 41 | -1697705 |
| 42 | -486131 |
| 43 | -3447 |
| 44 | 0 |
| 45 | 1 |
| 46 | -1 |
| 47 | -127 |
| 48 | -46529 |
| 49 | -7946143 |
| 50 | -206659569 |
| 51 | -369575303 |
| 52 | -24266797 |
| 53 | -29093 |
| 54 | 0 |