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WeChall_Prime Factory (Training, Math)

Your task is simple:
Find the first two primes above 1 million, whose separate digit sums are also prime.
As example take 23, which is a prime whose digit sum, 5, is also prime.
The solution is the concatination of the two numbers,
Example: If the first number is 1,234,567
and the second is 8,765,432,
your solution is 12345678765432

 

解题:

素数打表,依次从小到达剔除素数的倍数的数。

def allsum(x):    sum = 0    while x:        sum += x%10        x //= 10    return sumtotal = 2000000prime = []a = [1 for i in range(total)]for i in range(2,total):    if a[i]:        prime.append(i)        time = 2        while 1:            num = time*i            if num >= total:                break            a[num] = 0            time += 1find = 0for i in range(1000000,total):    if i in prime and allsum(i) in prime:        print(i)        find += 1        if find == 2:            break

 

WeChall_Prime Factory (Training, Math)