OFFSET
1,1
COMMENTS
PROG
(Magma)
XOR := func<a, b | Seqint([ (adigs[i] + bdigs[i]) mod 2 : i in [1..n]], 2)
where adigs := Intseq(a, 2, n)
where bdigs := Intseq(b, 2, n)
where n := 1 + Ilog2(Max([a, b, 1]))>;
function IsClardynum(X, i)
if i eq 1 then
return true;
else
xornum:=2^i - 2;
xorcouple:=XOR(X, xornum);
if (IsPrime(xorcouple)) then
return false;
else
return IsClardynum(X, i-1);
end if;
end if;
end function;
for i:= 3 to 10001 by 2 do
if not IsPrime(i) then
if IsClardynum(i, Ilog2(i)) then i;
end if;
end if;
end for;
CROSSREFS
KEYWORD
nonn
AUTHOR
Brad Clardy, Apr 12 2012
STATUS
approved