

A055945


n  reversal of base 2 digits of n (and then the result is written in base 10).


4



0, 0, 1, 0, 3, 0, 3, 0, 7, 0, 5, 2, 9, 2, 7, 0, 15, 0, 9, 6, 15, 0, 9, 6, 21, 6, 15, 0, 21, 6, 15, 0, 31, 0, 17, 14, 27, 4, 13, 18, 35, 4, 21, 10, 31, 0, 17, 14, 45, 14, 31, 0, 41, 10, 27, 4, 49, 18, 35, 4, 45, 14, 31, 0, 63, 0, 33, 30, 51, 12, 21, 42, 63, 0, 33, 30, 51, 12, 21, 42, 75, 12, 45, 18, 63, 0, 33, 30, 75, 12, 45
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OFFSET

0,5


COMMENTS

a(n) is even if n is odd and a(n) is odd if n is even; this is caused by the kind of swapping the most significant and least significant binary digit when reversing n and the fact that the most significant digit of n is always 1.  R. J. Mathar, Nov 05 2015


LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..16384
Rémy Sigrist, Colored scatterplot of the first 2^16 terms (where the color is function of n mod 8)


FORMULA

For 2^m <= n <= 2^(m+1), we have n  2^(m+1) <= a(n) <= n.  N. J. A. Sloane, May 29 2016
a(n) = n  A030101(n).


MAPLE

a:= proc(n) local m, r; m:=n; r:=0;
while m>0 do r:= r*2 +irem(m, 2, 'm') od;
nr
end:
seq(a(n), n=0..100); # Alois P. Heinz, Jul 02 2015


MATHEMATICA

Array[#  IntegerReverse[#, 2] &, 90] (* Michael De Vlieger, Sep 06 2019 *)


CROSSREFS

Cf. A030101, A030109, A265326.
Sequence in context: A045763 A132748 A022901 * A138123 A328382 A211868
Adjacent sequences: A055942 A055943 A055944 * A055946 A055947 A055948


KEYWORD

base,sign,look


AUTHOR

Henry Bottomley, Jul 18 2000


STATUS

approved



