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A035928 Numbers n such that BCR(n) = n, where BCR = binary-complement-and-reverse = take one's complement then reverse bit order. 24
2, 10, 12, 38, 42, 52, 56, 142, 150, 170, 178, 204, 212, 232, 240, 542, 558, 598, 614, 666, 682, 722, 738, 796, 812, 852, 868, 920, 936, 976, 992, 2110, 2142, 2222, 2254, 2358, 2390, 2470, 2502, 2618, 2650, 2730, 2762, 2866, 2898, 2978, 3010, 3132, 3164 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A036044(n) = n.

Also: numbers such that n+BR(n) is in A000225={2^k-1} (with BR = binary reversed). - M. F. Hasler, Dec 17 2007

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Aayush Rajasekaran, Jeffrey Shallit, and Tim Smith, Sums of Palindromes: an Approach via Nested-Word Automata, preprint arXiv:1706.10206 [cs.FL], June 30 2017.

FORMULA

If offset were 0, a(2n+1) - a(2n) = 2^[log2(n)+1].

EXAMPLE

38 is such a number because 38=100110; complement to get 011001, then reverse bit order to get 100110.

MAPLE

[seq(ReflectBinSeq(j, (floor_log_2(j)+1)), j=1..256)];

ReflectBinSeq := (x, n) -> (((2^n)*x)+binrevcompl(x));

binrevcompl := proc(nn) local n, z; n := nn; z := 0; while(n <> 0) do z := 2*z + ((n+1) mod 2); n := floor(n/2); od; RETURN(z); end;

floor_log_2 := proc(n) local nn, i: nn := n; for i from -1 to n do if(0 = nn) then RETURN(i); fi: nn := floor(nn/2); od: end; # Computes essentially the same as floor(log[2](n))

MATHEMATICA

bcrQ[n_]:=Module[{idn2=IntegerDigits[n, 2]}, Reverse[idn2/.{1->0, 0->1}] == idn2]; Select[Range[3200], bcrQ] (* Harvey P. Dale, May 24 2012 *)

PROG

(PARI) for(n=1, 1000, l=length(binary(n)); b=binary(n); if(sum(i=1, l, abs(component(b, i)-component(b, l+1-i)))==l, print1(n, ", ")))

(PARI) for(i=0, 999, if(Set(vecextract(t=binary(i), "-1..1")+t)==["1"], print1(i", "))) - M. F. Hasler, Dec 17 2007

(Haskell)

a035928 n = a035928_list !! (n-1)

a035928_list = filter (\x -> a036044 x == x) [0, 2..]

-- Reinhard Zumkeller, Sep 16 2011

CROSSREFS

Cf. A061855.

Cf. A000225.

Intersection of A195064 and A195066; cf. A195063, A195065.

Sequence in context: A176978 A186630 A154391 * A014486 A166751 A216649

Adjacent sequences:  A035925 A035926 A035927 * A035929 A035930 A035931

KEYWORD

nonn,nice,easy,base

AUTHOR

Mike Keith (domnei(AT)aol.com)

EXTENSIONS

More terms from Erich Friedman.

STATUS

approved

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Last modified February 24 14:41 EST 2018. Contains 299623 sequences. (Running on oeis4.)