A085429 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.

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, 57, 58, 66, 67, 70, 73, 75, 76, 77, 82, 85, 88, 92, 99, 101, 102, 103, 108, 109, 111, 121, 124, 126, 131, 135, 140, 141, 143, 146, 150, 151, 155, 161, 162, 165, 170, 171, 175, 177

Offset

0,3

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

143 is in the sequence because 143 = 10001111_2 and 341 = 101010101_2; both have five 1's.

Mathematica

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 *)
Select[Range[0, 200], DigitCount[#, 2, 1]==DigitCount[IntegerReverse[#], 2, 1]&] (* Harvey P. Dale, Jan 31 2025 *)

Crossrefs

Cf. A000120, A004086.

Sequence in context: A263364 A296242 A331020 * A202940 A082324 A219955

Adjacent sequences: A085426 A085427 A085428 * A085430 A085431 A085432

Keyword

base,easy,nonn

Author

Jason Earls, Aug 18 2003

Status

approved