|
%I #20 Nov 16 2019 20:04:22
%S 5,9,10,11,13,17,18,19,20,21,22,23,25,27,29,33,34,35,36,37,38,39,40,
%T 41,42,43,44,45,46,47,49,50,51,53,54,55,57,59,61,65,66,67,68,69,70,71,
%U 72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,97,98,99,101,102,103,105,107,108,109,110,111
%N Numbers n for which A256999(n) > n; numbers that can be made larger by rotating (by one or more steps) the non-msb bits of their binary representation (with A080541 or A080542).
%C Note that A256999(a(n)) is always in A257250.
%C If we define a co-necklace to be a finite sequence that is lexicographically maximal (not minimal) among all of its cyclic rotations, these are numbers whose binary expansion, without the most significant digit, is not a co-necklace. Numbers whose binary expansion, without the most significant digit, is not a necklace are A329367. - _Gus Wiseman_, Nov 14 2019
%H Antti Karttunen, <a href="/A257739/b257739.txt">Table of n, a(n) for n = 1..10000</a>
%e For n = 5 with binary representation "101" if we rotate other bits than the most significant bit (that is, only the two rightmost digits "01") one step to either direction we get "110" = 6 > 5, so 5 can be made larger by such rotations and thus 5 is included in this sequence.
%e For n = 6 with binary representation "110" no such rotation will yield a larger number and thus 6 is NOT included in this sequence.
%e For n = 10 with binary representation "1010" if we rotate other bits than the most significant bit (that is, only the three rightmost digits "010") either one step to the left or two steps to the right we get "1100" = 12 > 10, thus 10 is included in this sequence.
%t reckQ[q_]:=Array[OrderedQ[{RotateRight[q,#],q}]&,Length[q]-1,1,And];
%t Select[Range[2,100],!reckQ[Rest[IntegerDigits[#,2]]]&] (* _Gus Wiseman_, Nov 14 2019 *)
%o (Scheme, with _Antti Karttunen_'s IntSeq-library)
%o (define A257739 (MATCHING-POS 1 1 (lambda (n) (< n (A256999 n)))))
%Y Complement: A257250.
%Y Cf. A080541, A080542, A256999.
%Y Numbers whose binary expansion is a necklace are A275692.
%Y Numbers whose binary expansion is a co-necklace are A065609.
%Y Numbers whose reversed binary expansion is a necklace are A328595.
%Y Numbers whose non-msb expansion is a co-necklace are A257250.
%Y Numbers whose non-msb expansion is a necklace are A328668.
%Y Numbers whose reversed non-msb expansion is a necklace are A328607.
%Y Numbers whose non-msb expansion is not a necklace are A329367.
%Y Binary necklaces are A000031.
%Y Necklace compositions are A008965.
%Y Cf. A000120, A001037, A003714, A014081, A121016, A164707, A328594, A328596.
%K nonn,base
%O 1,1
%A _Antti Karttunen_, May 18 2015
|
