1 |
n+1 |
2 |
n+1 |
3 |
n+1 |
n |
n+1 |
n(n+1) |
2(n+1) |
n |
2 |
数列{bn}={
1 |
anan+1 |
1 |
anan+1 |
2 |
n |
2 |
n+1 |
1 |
n |
1 |
n+1 |
其前n项的和为4[(
1 |
1 |
1 |
2 |
1 |
2 |
1 |
3 |
1 |
3 |
1 |
4 |
1 |
n |
1 |
n+1 |
1 |
n+1 |
故选A
1 |
2 |
1 |
3 |
2 |
3 |
1 |
4 |
2 |
4 |
3 |
4 |
1 |
5 |
2 |
5 |
3 |
5 |
4 |
5 |
1 |
anan+1 |
1 |
n+1 |
1 |
2 |
1 |
n+1 |
1 |
n+1 |
1 |
2 |
1 |
n+1 |
1 |
n+1 |
2 |
n+1 |
3 |
n+1 |
n |
n+1 |
n(n+1) |
2(n+1) |
n |
2 |
1 |
anan+1 |
1 |
anan+1 |
2 |
n |
2 |
n+1 |
1 |
n |
1 |
n+1 |
1 |
1 |
1 |
2 |
1 |
2 |
1 |
3 |
1 |
3 |
1 |
4 |
1 |
n |
1 |
n+1 |
1 |
n+1 |