This seems to work pretty close to what the table shows
void setup() {
double Alt;
double PF= 450;
double PS=1013;
double div = -6.8755856E-6;
Serial.begin(9600);
double param, result;
param = log10 (PF/PS);
result = pow(10,param/5.255856)-1 ;
Alt = result/div;
Serial.println (Alt );
}
void loop() {
//do nothing
}