

A140900


A nonnegative integer n is included if the binary representation of n and the digitreversal (with leading 0's) of the binary representation of n do not have any 1's in the same position.


5



0, 2, 4, 8, 10, 12, 16, 18, 24, 32, 34, 36, 38, 40, 42, 48, 52, 56, 64, 66, 68, 70, 80, 82, 96, 100, 112, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 160, 162, 168, 170, 176, 178, 192, 196, 200, 204, 208, 212, 224, 232, 240, 256, 258, 260, 262, 264
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OFFSET

1,2


COMMENTS

All terms of this sequence are even.
Number of terms less than or equal to 10^n: 1, 5, 26, 162, 1045, 5976, 38980, 249229, 1416583, 9381238, ..., .  Robert G. Wilson v, Aug 04 2008
Number of terms < 2^k: 1, 2, 3, 6, 18, 27, 54, 81,... (A038754).  T. D. Noe, Apr 09 2009


LINKS



EXAMPLE

36 in binary is 100100. The digitreversal (with leading 0's) of this is 001001. These binary representations have no 1's in the same location (i.e., they can be added in binary without any carries). So 36 is in this sequence.


MATHEMATICA

fQ[n_] := Block[{id = IntegerDigits[n, 2]}, Max@ Union[id + Reverse@ id] < 2]; Select[2 Range[0, 134], fQ@# &] (* Robert G. Wilson v, Aug 04 2008 *)


PROG

(PARI) is(n) = my (b=if (n, binary(n), [0])); vecmax(b+Vecrev(b))<=1 \\ Rémy Sigrist, Jun 11 2022


CROSSREFS



KEYWORD

base,nonn


AUTHOR



EXTENSIONS



STATUS

approved



