An |
Bn |
7n+45 |
n+3 |
an |
bn |
A.2 | B.3 | C.4 | D.5 |
an |
bn |
| ||
|
| ||
|
A2n-1 |
B2n-1 |
7(2n-1)+45 |
(2n-1)+3 |
14n+38 |
2n+2 |
7n+19 |
n+1 |
12 |
n+1 |
an |
bn |
S3-S2 |
S5-S3 |
A.2 | B.3 | C.
| D.不存在 |
A.S7 | B.S7或S8 | C.S14 | D.S8 |
A.260 | B.168 | C.156 | D.130 |
1 |
anan+1 |
A.450 | B.470 | C.490 | D.510 |
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