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A182302 Composite numbers that are not perfect powers whose prime factors have equal numbers of bits. 2

%I #6 Apr 30 2012 13:53:10

%S 6,12,18,24,35,48,54,72,96,108,143,162,175,192,245,288,323,384,391,

%T 432,437,486,493,527,551,589,648,667,713,768,864,875,899,972,1152,

%U 1458,1517,1536,1573,1591,1715,1739,1763,1859,1927,1944,1961,2021,2173,2183,2257

%N Composite numbers that are not perfect powers whose prime factors have equal numbers of bits.

%H Arkadiusz Wesolowski, <a href="/A182302/b182302.txt">Table of n, a(n) for n = 1..10000</a>

%e 35 = 5*7 -> 101*111, therefore 35 is a term.

%e 36 = 6^2 -> 10*10*11*11, therefore 36 is not a term.

%t 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

%Y Subsequence of A200878.

%K base,nonn

%O 1,1

%A _Arkadiusz Wesolowski_, Apr 23 2012

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Last modified July 15 02:08 EDT 2024. Contains 374323 sequences. (Running on oeis4.)