/* Ackermann function */
proc ack(word m, n) word:
    if   m=0 then n+1
    elif n=0 then ack(m-1, 1)
    else          ack(m-1, ack(m, n-1))
    fi
corp;

/* Write a table of Ackermann values */
proc nonrec main() void:
    byte m, n;
    for m from 0 upto 3 do
        for n from 0 upto 8 do
            write(ack(m,n) : 5)
        od;
        writeln()
    od
corp