A043017 n-th base 7 palindrome that starts with 3.

3, 24, 150, 157, 164, 171, 178, 185, 192, 1032, 1088, 1144, 1200, 1256, 1312, 1368, 7206, 7255, 7304, 7353, 7402, 7451, 7500, 7556, 7605, 7654, 7703, 7752, 7801, 7850, 7906, 7955, 8004, 8053, 8102, 8151, 8200, 8256, 8305