A224694 - OEIS

%I #24 Feb 09 2020 10:54:37

%S 0,2,4,8,10,12,16,18,24,26,32,34,36,40,44,48,50,56,64,66,68,76,80,90,

%T 96,98,100,108,112,128,130,132,136,138,144,146,152,160,164,168,176,

%U 184,192,194,196,208,224,228,240,256,258,260,264,266,268,280,282,288,290,296,312

%N Numbers n such that n^2 AND n = 0, where AND is the bitwise logical AND operator.

%C Indices of zeros in A213541.

%C The sequence b(n) = a(n)/2  begins: 0, 1, 2, 4, 5, 6, 8, 9, 12, 13, 16, 17, 18, 20, 22, 24, 25, 28, 32, 33, 34, 38, 40, 45, 48, 49, 50, 54, 56, 64

%H Reinhard Zumkeller, <a href="/A224694/b224694.txt">Table of n, a(n) for n = 1..10000</a>

%p read("transforms") :

%p isA224694 := proc(n)

%p     return( ANDnos(n^2,n) =0 ) ;

%p end proc:

%p A224694 := proc(n)

%p     option remember;

%p     if n = 1 then

%p         0;

%p     else

%p         for a from procname(n-1)+1 do

%p             if isA224694(a) then

%p                 return a;

%p             end if;

%p         end do:

%p     end if;

%p end proc: # _R. J. Mathar_, Apr 25 2013

%t Select[Range[0, 350], BitAnd[#^2, #] == 0 &] (* _Matthew House_, Jul 14 2015 *)

%o (Python)

%o for i in range(333):

%o     if ((i*i) & i)==0:

%o       print str(i)+',',

%o (Haskell)

%o import Data.List (elemIndices)

%o a224694 n = a224694_list !! (n-1)

%o a224694_list = elemIndices 0 a213541_list

%o -- _Reinhard Zumkeller_, Apr 25 2013

%Y Cf. A213541.

%K nonn,easy,base

%O 1,2

%A _Alex Ratushnyak_, Apr 15 2013