val isPrime = fn(i number) {
	i == 2 or i > 2 and
		not any(series(2 .. i ^/ 2, asconly=true), by=fn(x) { i div x })
}

val sumDigits = fn(i) { fold(s2n(string(i)), by=fn{+}) }

writeln "Additive primes less than 500:"

var cnt = 0

for i in [2] ~ series(3..500, inc=2) {
    if isPrime(i) and isPrime(sumDigits(i)) {
        write "{{i:3}}  "
        cnt += 1
        if cnt div 10: writeln()
    }
}

writeln "\n\n{{cnt}} additive primes found.\n"