题干
观察下列各式：
=
=
−
，
=
=
−
，
=
=
−
，
=
=
−
，
=
=
−
，…
| 1 |
| 2 |
| 1 |
| 1 |
| 2 |
| 1 |
| 1 |
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 2 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 1 |
| 3 |
| 4 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 1 |
| 4 |
| 5 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 1 |
| 5 |
| 6 |
| 1 |
| 5 |
| 1 |
| 6 |
