1000.primes.map_reduce {|a,b| a + b }.map_kv {|k,v|
    [k+1, prime(k+1), v]
}.grep { .tail.is_prime }.prepend(
    ['count', 'prime', 'sum']
).each_2d {|n,p,s|
    printf("%5s %6s %8s\n", n, p, s)
}