A182302 Composite numbers that are not perfect powers whose prime factors have equal numbers of bits.
6, 12, 18, 24, 35, 48, 54, 72, 96, 108, 143, 162, 175, 192, 245, 288, 323, 384, 391, 432, 437, 486, 493, 527, 551, 589, 648, 667, 713, 768, 864, 875, 899, 972, 1152, 1458, 1517, 1536, 1573, 1591, 1715, 1739, 1763, 1859, 1927, 1944, 1961, 2021, 2173, 2183, 2257
Offset: 1
Examples
35 = 5*7 -> 101*111, therefore 35 is a term. 36 = 6^2 -> 10*10*11*11, therefore 36 is not a term.
Links
- Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000
Crossrefs
Subsequence of A200878.
Programs
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Mathematica
lst1 = {}; lst2 = {}; r = 2257; Do[b = IntegerDigits[FactorInteger[n], 2]; If[! PrimeQ[n] && Length[b[[-1, 1]]] == Length[b[[1, 1]]], AppendTo[lst1, n]], {n, 4, r}]; lst2 = Complement[lst1, Union[Flatten[Table[n^i, {i, 2, Log[2, r]}, {n, 2, r^(1/i)}]]]]; lst2