a(n+1)=2an +1a(n+1)+1=2(an +1)[a(n+1)+1]/(an +1)=2数列{an+1}是等比数列,首项为2;公比为2an+1=2*2^(n-1)=2^nan=2^n-1
a(n+1)=2an +1a(n+1)+1=2an +1+1a(n+1)+1=2(an +1)[a(n+1)+1]/(an +1)=2所以数列{an+1}是等比数列,首项为(a1 +1),公比为2an+1=(a1+1)*2^(n-1)通é