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 | -4 |
| 5 | 1 |
| 6 | -10 |
| 7 | 9 |
| 8 | 1 |
| 9 | -20 |
| 10 | 64 |
| 11 | 1 |
| 12 | -35 |
| 13 | 259 |
| 14 | -225 |
| 15 | 1 |
| 16 | -56 |
| 17 | 784 |
| 18 | -2304 |
| 19 | 1 |
| 20 | -84 |
| 21 | 1974 |
| 22 | -12916 |
| 23 | 11025 |
| 24 | 1 |
| 25 | -120 |
| 26 | 4368 |
| 27 | -52480 |
| 28 | 147456 |
| 29 | 1 |
| 30 | -165 |
| 31 | 8778 |
| 32 | -172810 |
| 33 | 1057221 |
| 34 | -893025 |
| 35 | 1 |
| 36 | -220 |
| 37 | 16368 |
| 38 | -489280 |
| 39 | 5395456 |
| 40 | -14745600 |
| 41 | 1 |
| 42 | -286 |
| 43 | 28743 |
| 44 | -1234948 |
| 45 | 21967231 |
| 46 | -128816766 |
| 47 | 108056025 |
| 48 | 1 |
| 49 | -364 |
| 50 | 48048 |
| 51 | -2846272 |
| 52 | 75851776 |
| 53 | -791691264 |
| 54 | 2123366400 |