cp's OEIS Frontend

A232710 Binary numbers (written in decimal) such that the sum of digits mod 2 equals the product of digits mod 2.

%I A232710 #12 Dec 04 2013 13:19:22
%S A232710 0,1,5,6,7,9,10,12,17,18,20,23,24,27,29,30,31,33,34,36,39,40,43,45,46,
%T A232710 48,51,53,54,57,58,60,65,66,68,71,72,75,77,78,80,83,85,86,89,90,92,95,
%U A232710 96,99,101,102,105,106,108,111,113,114,116,119,120,123,125
%N A232710 Binary numbers (written in decimal) such that the sum of digits mod 2 equals the product of digits mod 2.
%H A232710 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A232710 A083420 UNION (A001969 \ {3}). - _Ralf Stephan_, Nov 30 2013
%e A232710 23 is in the sequence because 23 in binary is 10111. The sum of digits is 4 == 0 mod 2 and the products of digits is 0 == 0 mod 2.
%o A232710 (JavaScript)
%o A232710 for (i=0;i<1000;i++) {
%o A232710 s=i.toString(2).split("");
%o A232710 sl=s.length;
%o A232710 c=0;d=1;
%o A232710 for (j=0;j<sl;j++) {c+=s[j]*1;d*=s[j];}
%o A232710 c%=2;d%=2;
%o A232710 if (c==d) document.write(i+", ");
%o A232710 }
%o A232710 (PARI) is(n)=b=binary(n);sum(i=1,#b,b[i])%2==prod(i=1,#b,b[i])%2 \\ _Ralf Stephan_, Nov 30 2013
%K A232710 nonn,base
%O A232710 0,3
%A A232710 _Jon Perry_, Nov 28 2013