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#f9e69df9-820a-43be-bd72-6c981d92f789中等解答题数列求和方法数列

30.(2023•温州模拟)设SnS_{n}为正项数列{an}\{a_{n}\}的前nn项和,满足2Sn=an2+an22S_{n}={a}_{n}^{2}+a_{n}-2
(I)(I){an}\{a_{n}\}的通项公式;
(II)(II)若不等式(1+2an+t)  an4(1+\frac{2}{{a}_{n}+t}){\;}^{{a}_{n}}\geqslant 4对任意正整数nn都成立,求实数tt的取值范围;
(Ⅲ)设bn=e34anln(n+1)b_{n}={e}^{\frac{3}{4}{a}_{n}ln(n+1)}(其中rr是自然对数的底数),求证:b1b3+b2b4++bnbn+2<66\frac{{b}_{1}}{{b}_{3}}+\frac{{b}_{2}}{{b}_{4}}+\ldots +\frac{{b}_{n}}{{b}_{n+2}}<\frac{\sqrt{6}}{6}