Returns the Fermat number 2^2^n + 1
a 1x1 matrix of floating point integers, must be positive
a 1x1 matrix of floating point integers
Returns the Fermat number :
number_fermat ( 0 ) // 3 number_fermat ( 1 ) // 5 number_fermat ( 2 ) // 17 number_fermat ( 3 ) // 257 number_fermat ( 4 ) // 65537 number_fermat ( 5 ) // 641*6700417