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

1,1

Links

Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000

Example

35 = 5*7 -> 101*111, therefore 35 is a term.
36 = 6^2 -> 10*10*11*11, therefore 36 is not a term.

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

Crossrefs

Subsequence of A200878.

Sequence in context: A277723 A033018 A189781 * A358757 A353530 A244193

Adjacent sequences: A182299 A182300 A182301 * A182303 A182304 A182305

Keyword

base,nonn

Author

Arkadiusz Wesolowski, Apr 23 2012

Status

approved