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设数列{an}为等差数列,其前n项和为Sn,已知a1+a4+a7=99,a2+a...
设数列{an}为等差数列,其前n项和为Sn,已知a1+a4+a7=99,a2+a5+a8=93,若对任意n∈N*,都有Sn≤Sk成立,则k的值为( )
A.22
B.21
C.20
D.19
考点分析:
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