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 | 3 |
| 4 | -4 |
| 5 | 1 |
| 6 | 9 |
| 7 | -15 |
| 8 | 7 |
| 9 | -1 |
| 10 | 27 |
| 11 | -54 |
| 12 | 36 |
| 13 | -10 |
| 14 | 1 |
| 15 | 81 |
| 16 | -189 |
| 17 | 162 |
| 18 | -66 |
| 19 | 13 |
| 20 | -1 |
| 21 | 243 |
| 22 | -648 |
| 23 | 675 |
| 24 | -360 |
| 25 | 105 |
| 26 | -16 |
| 27 | 1 |
| 28 | 729 |
| 29 | -2187 |
| 30 | 2673 |
| 31 | -1755 |
| 32 | 675 |
| 33 | -153 |
| 34 | 19 |
| 35 | -1 |
| 36 | 2187 |
| 37 | -7290 |
| 38 | 10206 |
| 39 | -7938 |
| 40 | 3780 |
| 41 | -1134 |
| 42 | 210 |
| 43 | -22 |
| 44 | 1 |
| 45 | 6561 |
| 46 | -24057 |
| 47 | 37908 |
| 48 | -34020 |
| 49 | 19278 |
| 50 | -7182 |
| 51 | 1764 |
| 52 | -276 |
| 53 | 25 |
| 54 | -1 |
| 55 | 19683 |
| 56 | -78732 |
| 57 | 137781 |
| 58 | -139968 |
| 59 | 91854 |
| 60 | -40824 |
| 61 | 12474 |
| 62 | -2592 |
| 63 | 351 |
| 64 | -28 |
| 65 | 1 |