设等差数列{an}的前n项和为Sn,且a2=2,s4=14.求{an}的通项公式接上 (1)求{an}的通项公式.(2)若不等式2Sn+8n+27大于(-1)nK(an+4) 对所有的正整数n都成立,求实数k的取值范围
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