TURKISH JOURNAL OF MATHEMATICS, cilt.42, sa.4, ss.1990-1999, 2018 (SCI-Expanded)
Let m be a positive integer. We show that the exponential Diophantine equation (18m(2) + 1)(x) + (7m(2) - 1)(y) = (5m)(z) has only the positive integer solution (x, y, z) = (1, 1, 2) except for m 23, 47, 63, 87 (mod 120) . For m not equivalent to 0 (mod 5) we use some elementary methods and linear forms in two logarithms. For m 0 (mod 5) we apply a result for linear forms in p-adic logarithms.