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急 一到数列题[x]表示不超过实数X的最大整数,比如[3.14]=3,[0]=0,[-3.14]=-4.数列{an}满足

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急 一到数列题
[x]表示不超过实数X的最大整数,比如[3.14]=3,[0]=0,[-3.14]=-4.数列{an}满足:an=3n-2,若bn=[an/5],则b1+b2+…+b2007=?
急 一到数列题[x]表示不超过实数X的最大整数,比如[3.14]=3,[0]=0,[-3.14]=-4.数列{an}满足
a₁ = 1, b₁ = 0
a₂ = 4, b₂ = 0
a₃ = 7, b₃ = 1
a₄ = 10, b₄ = 2
a5 = 13, b5 = 2 b₁+ b₂+ b₃+ b₄+ b5 = 5
a6 = 16, b6 = 3
a7 = 19, b7 = 3
a8 = 21, b8 = 4
a9 = 25, b9 = 5
a10 = 28, b10 = 5 b6 + b7 + b8 + b9 + b10 = 20
a11 = 31, b10 = 6
a12 = 34, b10 = 6
a13 = 37, b10 = 7
a14 = 40, b10 = 8
a15 = 43, b10 = 8 b11 + b12 + b13+ b14 + b15 = 35
.
规律是:5 + 20 + 35 + .
项数 = 2005 ÷ 5 = 401
数列 :5 + 20 + 35 + . + (5+400×15) = (5+6000)×401÷2 = 1205005
a2006 = 3×2006 - 2 = 6016, b2006 =6016÷5 = 1203
a2007 = 3×2007 - 2 = 6019, b2006 =6016÷5 = 1203
最后答案:
b₁+ b₂+ b₃+ b₄+ b5 + .+ b2007 = 1205005 + 1203 + 1203 = 1207411