MATLAB: Error in If else statement

Hi I am getting error in if else statement but dont know where is the mistake.

Points=[];
for i=1:257
     if i == 16 & i == 136
     a=mod(i*(modInv(32*i+1,n)),n);  
     else
         a=mod(i*(modInv(16*i+1,n)),n);
     end
     b(i)=mod(a,n);
 end
 Points=[b];

For i= 16 or 136 it should execute line3 but it gives NaN at i=16 and i=136

If anyone can help me what is the mistake

Correct answer for i=16 is 241 and for i=136 is 120

Best Answer