please help -problem in m-file for PN code generation

i use this code for generating a PN code and the matlab show me this error " ??? Undefined function or method 'PN' for input arguments of type 'char'.

please help me what the error in code



%PN_sequence_generation.m
clear
clc
G=63; % Code length
%Generation of first m-sequence using generator polynomial [45]
sd1 =[0 0 0 0 1]; % Initial state of Shift register
PN1=[]; % First m-sequence
for j=1:G
PN1=[PN1 sd1(5)];
if sd1(1)==sd1(4)
temp1=0;
else temp1=1;
end
sd1(1)=sd1(2);
sd1(2)=sd1(3);
sd1(3)=sd1(4);
sd1(4)=sd1(5);
sd1(5)=temp1;
end
subplot(3,1,1)
stem(PN1)
title('M-sequence generated by generator polynomial [45]')

%Generation of second m-sequence using generator polynomial [67]
sd2 =[0 0 0 0 1]; % Initial state of Shift register
PN2=[]; % Second m-sequence
for j=1:G
PN2=[PN2 sd2(5)];
if sd2(1)==sd2(2)
temp1=0;
else temp1=1;
end
if sd2(4)==temp1
temp2=0;
else temp2=1;
end
if sd2(5)==temp2
temp3=0;
else temp3=1;
end
sd2(1)=sd2(2);
sd2(2)=sd2(3);
sd2(3)=sd2(4);
sd2(4)=sd2(5);
sd2(5)=temp3;
end
subplot(3,1,2)
stem(PN2)
title('M-sequence generated by generator polynomial [67]')

%Generation of Third m-sequence using generator polynomial [75]
sd3 =[0 0 0 0 1]; % Initial state of Shift register
PN3=[]; % Third m-sequence
for j=1:G
PN3=[PN3 sd3(5)];
if sd3(1)==sd3(2)
temp1=0;
else temp1=1;
end
if sd3(3)==temp1
temp2=0;
else temp2=1;
end
if sd3(4)==temp2
temp3=0;
else temp3=1;
end
sd3(1)=sd3(2);
sd3(2)=sd3(3);
sd3(3)=sd3(4);
sd3(4)=sd3(5);
sd3(5)=temp3;
end
subplot(3,1,3)
stem(PN3)
title('M-sequence generated by generator polynomial [75]')

where is the error, i run it on my computer and it's working fine...