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%I #11 Apr 13 2024 20:08:58
%S 0,1,2,3,4,5,6,7,8,9,11,14,15,22,25,28,29,33,37,41,44,45,51,52,54,55,
%T 57,58,66,67,70,73,75,76,77,82,85,88,92,99,101,102,103,108,109,111,
%U 121,124,126,131,135,140,141,143,146,150,151,155,161,162,165,170,171,175,177
%N Numbers k such that the number of 1's in the binary expansion of k is equal to the number of 1's in the binary expansion of the reversal of k.
%e 143 is in the sequence because 143 = 10001111_2 and 341 = 101010101_2; both have five 1's.
%t dc1Q[n_]:=Module[{rev=FromDigits[Reverse[IntegerDigits[n]]]}, DigitCount[n,2,1] ==DigitCount[rev,2,1]]; Select[Range[0,250],dc1Q] (* _Harvey P. Dale_, Apr 03 2011 *)
%Y Cf. A000120, A004086.
%K base,easy,nonn
%O 0,3
%A _Jason Earls_, Aug 18 2003