Erdős-primes

func is_erdos_prime(p) {

    return true  if p==2
    return false if !p.is_prime

    var f = 1

    for (var k = 2; f < p; k++) {
        p - f -> is_composite || return false
        f *= k
    }

    return true
}

say ("Erdős primes <= 2500: ", 1..2500 -> grep(is_erdos_prime))
say ("The 7875th Erdős prime is: ", is_erdos_prime.nth(7875))

Output:

Erdős primes <= 2500: [2, 101, 211, 367, 409, 419, 461, 557, 673, 709, 769, 937, 967, 1009, 1201, 1259, 1709, 1831, 1889, 2141, 2221, 2309, 2351, 2411, 2437]
The 7875th Erdős prime is: 999721