A091066 - OEIS

%I #20 Feb 05 2016 02:50:07

%S 3,5,7,9,10,11,13,15,17,18,19,21,22,23,25,27,29,31,33,34,35,36,37,38,

%T 39,41,42,43,45,46,47,49,51,53,54,55,57,59,61,63,65,66,67,68,69,70,71,

%U 73,74,75,76,77,78,79,81,82,83,85,86,87,89,90,91,93,94,95,97,99,101

%N Numbers having in binary representation at least one proper prefix that is also a suffix.

%C A091064(a(n)) > 0, complement of A091065.

%C Includes all odd numbers > 1. - _Robert Israel_, Feb 05 2016

%H Alois P. Heinz, <a href="/A091066/b091066.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%p f:= proc(n) local L,m;

%p    if n::odd then return true fi;

%p    L:= convert(n,base,2);

%p    for m from 2 to nops(L)-1 do

%p      if L[1..m] = L[-m..-1] then return true fi;

%p    od:

%p    false

%p end proc:

%p select(f, [$2..101]); # _Robert Israel_, Feb 05 2016

%Y Cf. A007088, A070939, A082461, A242869.

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Dec 17 2003