1 |
a1a2 |
1 |
a2a3 |
1 |
anan+1 |
|
1 |
a1a2 |
1 |
4×5 |
1 |
anan+1 |
1 |
(2n+1)(2n+3) |
1 |
2 |
1 |
2n+1 |
1 |
2n+3 |
1 |
4×5 |
1 |
2 |
1 |
5 |
1 |
7 |
1 |
7 |
1 |
9 |
1 |
2n+1 |
1 |
2n+3 |
1 |
20 |
1 |
2 |
1 |
5 |
1 |
2n+3 |
3 |
20 |
1 |
2(2n+3) |
n |
an |
1 | ||
3x+
|
A.
| B.13
| C.
| D.
|
1 |
3 |
1 |
9 |
1 |
27 |
1 |
3n |
2n |
bn |
A.90 | B.45 | C.30 | D.
|
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