SEXY PRIMES SEQUENCE

I stumbled across this post and this is what I came out...

Sexy primes are pairs of primes of the form (p, p+6).

The challenge was to devise a D program outputing something like:

(5,11), (7,13), (11,17), (13,19), (17,23), (23,29), (31,37), (37,43), (41,47), (47,53), (53,59), (61,67), (67,73), (73,79), (83,89), (97,103), (101,107), (103,109), (107,113), (131,137), (151,157), (157,163), (167,173), (173,179), (191,197), (193,199), (223,229), (227,233), (233,239), (251,257), (257,263), (263,269), (271,277), (277,283), (307,313), (311,317), (331,337), (347,353), (353,359), (367,373), (373,379), (383,389), (433,439), (443,449), (457,463), (461,467)

Source code

import std.stdio;

void findSexyPrimes(in int lower, in int upper) {
    // Prime sieve
    auto isPrime = new bool[upper + 1];
    isPrime[2..$] = true;

    for (int i = 2; i * i <= upper; ++i) {
        if (isPrime[i]) {
            for (int j = i * i; j <= upper; j += i) {
                isPrime[j] = false;
            }
        }
    }
    
    // Outputting sexy primes
    foreach (i; lower..upper - 6) {
        if (isPrime[i] && isPrime[i + 6]) {
            writef("(%d,%d), ", i, i + 6);
        }
    }
}

void main() {
    const LOWERBOUND = 2; // Lower bound
    const UPPERBOUND = 500; // Upper bound
    
    findSexyPrimes(LOWERBOUND, UPPERBOUND);
}

References

D language

Sexy primes Wikipedia entry

Sexy primes Rosetta Code wiki

Sexy primes Wolfram Mathworld page

Online Encyclopedia of Integer Sequences (OEIS): A023201 & A046117