设{an}是正数组成的数列,其前n项和为Sn,且对于所有的正整数n,有4Sn=(an+1)2(I)求a1,a2的值;(II)求数列{an}的通项公式;(III)令b1=1,b2k=a2k-1+(-1)k,b2k+1=a2k+3k(k=1,2,3,…),求{bn}的前20项和T
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![设{an}是正数组成的数列,其前n项和为Sn,且对于所有的正整数n,有4Sn=(an+1)2(I)求a1,a2的值;(II)求数列{an}的通项公式;(III)令b1=1,b2k=a2k-1+(-1)k,b2k+1=a2k+3k(k=1,2,3,…),求{bn}的前20项和T](/uploads/image/z/10892680-16-0.jpg?t=%E8%AE%BE%7Ban%7D%E6%98%AF%E6%AD%A3%E6%95%B0%E7%BB%84%E6%88%90%E7%9A%84%E6%95%B0%E5%88%97%2C%E5%85%B6%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BASn%2C%E4%B8%94%E5%AF%B9%E4%BA%8E%E6%89%80%E6%9C%89%E7%9A%84%E6%AD%A3%E6%95%B4%E6%95%B0n%2C%E6%9C%894Sn%3D%EF%BC%88an%2B1%EF%BC%892%EF%BC%88I%EF%BC%89%E6%B1%82a1%2Ca2%E7%9A%84%E5%80%BC%EF%BC%9B%EF%BC%88II%EF%BC%89%E6%B1%82%E6%95%B0%E5%88%97%7Ban%7D%E7%9A%84%E9%80%9A%E9%A1%B9%E5%85%AC%E5%BC%8F%EF%BC%9B%EF%BC%88III%EF%BC%89%E4%BB%A4b1%3D1%2Cb2k%3Da2k-1%2B%EF%BC%88-1%EF%BC%89k%2Cb2k%2B1%3Da2k%2B3k%EF%BC%88k%3D1%2C2%2C3%2C%E2%80%A6%EF%BC%89%2C%E6%B1%82%7Bbn%7D%E7%9A%84%E5%89%8D20%E9%A1%B9%E5%92%8CT)
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