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If `sum_(i=1)^(7) i^(2)x_(i) = 1` and `sum_(i=1)^(7)(i+1)^(2) x_(i) = 12` and `sum_(i=1)^(7)(i+2)^(2)x_(i) = 123` then find the value of `sum_(i=1)^(7)(i+3)^(2)x_(i)”____”`