Question

有穷数列{an}}（n属于N*）满足a1=an,a2=an-1,…,an=a1,即ai=an-i+1（n属于N*且1≤i

Answer 1

a(1)=a(7)=2,a(2)=a(6),a(3)=a(5),a(4)=11.

a(2) = a(1) + d = 2+d,

a(3) = a(1) + 2d = 2 + 2d,

11 = a(4) = a(1) + 3d = 2 + 3d,d = 3.

a(1)=a(7)=2,

a(2)=a(6)=2+d=5,

a(3)=a(5)=2+2d=8,

a(4)=11