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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | -1 |
| 4 | 1 |
| 5 | -2 |
| 6 | 3 |
| 7 | -4 |
| 8 | 5 |
| 9 | -8 |
| 10 | 13 |
| 11 | -18 |
| 12 | 25 |
| 13 | -40 |
| 14 | 62 |
| 15 | -90 |
| 16 | 135 |
| 17 | -210 |
| 18 | 324 |
| 19 | -492 |
| 20 | 750 |
| 21 | -1164 |
| 22 | 1809 |
| 23 | -2786 |
| 24 | 4305 |
| 25 | -6710 |
| 26 | 10460 |
| 27 | -16264 |
| 28 | 25350 |
| 29 | -39650 |
| 30 | 62057 |
| 31 | -97108 |
| 32 | 152145 |
| 33 | -238818 |
| 34 | 375165 |
| 35 | -589520 |
| 36 | 927200 |
| 37 | -1459960 |
| 38 | 2300346 |
| 39 | -3626200 |