数列an满足a1=1,a2=2,an+2=(cos^2×nπ/2）an+sin^2×nπ/2,则2013=（） A.20

数列an满足a1=1,a2=2,an+2=(cos^2×nπ/2）an+sin^2×nπ/2,则2013=（） A.20 数列an满足a1=1,a2=2,a(n+2)=[1+cos^2(nπ/2)]an+sin^2(nπ/2)],n=1.2. 数列｛an｝满足a1=1,a2=2,an+2=[1+cos（nπ/2）]an+sin（nπ/2）,n=1,2,3… （1 一直数列{An}满足A1=1/2,A1+A2+…+An=n^2An 数列an中,a1=1,a2=2数列bn满足an+1+（-1）n次an,a属于N* （1）若an等差数列... 已知数列｛an｝满足：a1=1,且an-a（n-1）=2n.求a2,a3,a4.求数列｛an｝通项an 已知数列{an}满足：a1=20，a2=7，an+2-an=-2（n∈N*）． 数列{an}满足a1=1,a2=2,a(n+2)=(1+cos(nπ/2)^2)an+sin(nπ/2)^2,n=1,2 已知数列an满足an=1+2+...+n,且1/a1+1/a2+...+1/an 已知数列{an}中满足a1=1,a(n+1)=2an+1 (n∈N*),证明a1/a2+a2/a3+…+an/a(n+1 已知数列an满足条件a1=-2 a（n+1）=2an/(1-an) 则an= 已知数列{an}满足a1=1，a2=2，an+2=an+an+12，n∈N*．