考点1:等差数列与等比数列的综合问题高考真题1(2014年高考湖南理科卷第20题)已知数列{a_n}满足a_1=1,|a_(n+1)-a_n|=p~n,n∈N~*.(Ⅰ)若{a_n}是递增数列,且a_1,2a_2,3a_3成等差数列,求p的值;(Ⅱ)若p=1/2,且{a_(2n-1)}是递增数列,{a_(2n)}是递减数列,求数列{a_n}的通项公式.难度系数0.55 Test point 1: the arithmetic sequence of equal-difference series and the geometric ratio of the college entrance examination Zhenti 1 (2014 college entrance examination Hunan Science Volume 20) known sequence {a_n} satisfy a_1 = 1, | a_ (n +1) -a_n | = p ~ n, n∈N ~ *. (Ⅰ) Find the value of p if {a_n} is an increasing sequence and a_1,2a_2,3a_3 is an arithmetic progression. (Ⅱ) If p = 1/2 and {a_ 2n-1)} is an increasing sequence of numbers, {a_ (2n)} is a decreasing sequence,