mata
function ackermann(m,n) {
	if (m==0) {
		return(n+1)
	} else if (n==0) {
		return(ackermann(m-1,1))
	} else {
		return(ackermann(m-1,ackermann(m,n-1)))
	}
}

for (i=0; i<=3; i++) printf("%f\n",ackermann(i,4))
5
6
11
125
end