Problem 196
Prime triplets
Build a triangle from all positive integers in the following way:
1 | ||||||||||
2 | 3 | |||||||||
4 | 5 | 6 | ||||||||
7 | 8 | 9 | 10 | |||||||
11 | 12 | 13 | 14 | 15 | ||||||
16 | 17 | 18 | 19 | 20 | 21 | |||||
22 | 23 | 24 | 25 | 26 | 27 | 28 | ||||
29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | |||
37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | ||
46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | |
56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 |
.. | .. | .. |
Each positive integer has up to eight neighbours in the triangle.
A set of three primes is called a prime triplet if one of the three primes has the other two as neighbours in the triangle.
For example, in the second row, the prime numbers 2 and 3 are elements of some prime triplet.
If row 8 is considered, it contains two primes which are elements of some prime triplet, i.e. 29 and 31.
If row 9 is considered, it contains only one prime which is an element of some prime triplet: 37.
Define S(n) as the sum of the primes in row n which are elements of any prime triplet.
Then S(8)=60 and S(9)=37.
You are given that S(10000)=950007619.
Find S(5678027) + S(7208785).
素数三元组
将所有正整数按如下方式排列成三角形的样式:
1 | ||||||||||
2 | 3 | |||||||||
4 | 5 | 6 | ||||||||
7 | 8 | 9 | 10 | |||||||
11 | 12 | 13 | 14 | 15 | ||||||
16 | 17 | 18 | 19 | 20 | 21 | |||||
22 | 23 | 24 | 25 | 26 | 27 | 28 | ||||
29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | |||
37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | ||
46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | |
56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 |
.. | .. | .. |
每个正整数在三角形中有最多八个邻居。
如果三个素数中,有两个均为另一个的邻居,那么这一组三个素数被称为一个素数三元组。
例如,在第二行,素数2和3都是一些素数三元组的元素。
如果我们看第8行,将有两个素数属于某些素数三元组,这两个素数是29和31。
如果我们看第9行,只有一个素数属于某些素数三元组,这个素数是37。
记S(n)是第n行中属于某些素数三元组的素数之和。
因此S(8)=60,而S(9)=37。
已知S(10000)=950007619。
求S(5678027) + S(7208785)。