A018022 Powers of cube root of 16 rounded to nearest integer.

1, 3, 6, 16, 40, 102, 256, 645, 1625, 4096, 10321, 26008, 65536, 165140, 416128, 1048576, 2642246, 6658043, 16777216, 42275935, 106528681, 268435456, 676414963, 1704458901, 4294967296, 10822639410