If the length of the major axis, the length of the minor axis and the focal distance of an ellipse form an arithmetic sequence, then the eccentricity of the ellipse is zero______ .

If the length of the major axis, the length of the minor axis and the focal distance of an ellipse form an arithmetic sequence, then the eccentricity of the ellipse is zero______ .

According to the meaning of the question, 2a, 2b and 2c are equal difference sequence  2B = a + C  4B2 = A2 + 2Ac + C2  B2 = a2-c2  ②, 5c2 + 2ac-3a2 = 0  e = Ca  5e2 + 2e-3 = 0  0  e  1  e = 35, so the answer is: 35