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Cuban primes: Difference between revisions
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</lang>
=={{header|Java}}==
<lang Java>
public class CubanPrimes {
private static int MAX = 1_400_000;
private static boolean[] primes = new boolean[MAX];
public static void main(String[] args) {
preCompute();
cubanPrime(200, true);
for ( int i = 1 ; i <= 5 ; i++ ) {
int max = (int) Math.pow(10, i);
System.out.printf("%,d-th cuban prime = %,d%n", max, cubanPrime(max, false));
}
}
private static long cubanPrime(int n, boolean display) {
int count = 0;
long result = 0;
for ( long i = 0 ; count < n ; i++ ) {
long test = 1l + 3 * i * (i+1);
if ( isPrime(test) ) {
count++;
result = test;
if ( display ) {
System.out.printf("%10s%s", String.format("%,d", test), count % 10 == 0 ? "\n" : "");
}
}
}
return result;
}
private static boolean isPrime(long n) {
if ( n < MAX ) {
return primes[(int)n];
}
int max = (int) Math.sqrt(n);
for ( int i = 3 ; i <= max ; i++ ) {
if ( primes[i] && n % i == 0 ) {
return false;
}
}
return true;
}
private static final void preCompute() {
// primes
for ( int i = 2 ; i < MAX ; i++ ) {
primes[i] = true;
}
for ( int i = 2 ; i < MAX ; i++ ) {
if ( primes[i] ) {
for ( int j = 2*i ; j < MAX ; j += i ) {
primes[j] = false;
}
}
}
}
}
</lang>
{{out}}
<pre>
7 19 37 61 127 271 331 397 547 631
919 1,657 1,801 1,951 2,269 2,437 2,791 3,169 3,571 4,219
4,447 5,167 5,419 6,211 7,057 7,351 8,269 9,241 10,267 11,719
12,097 13,267 13,669 16,651 19,441 19,927 22,447 23,497 24,571 25,117
26,227 27,361 33,391 35,317 42,841 45,757 47,251 49,537 50,311 55,897
59,221 60,919 65,269 70,687 73,477 74,419 75,367 81,181 82,171 87,211
88,237 89,269 92,401 96,661 102,121 103,231 104,347 110,017 112,327 114,661
115,837 126,691 129,169 131,671 135,469 140,617 144,541 145,861 151,201 155,269
163,567 169,219 170,647 176,419 180,811 189,757 200,467 202,021 213,067 231,019
234,361 241,117 246,247 251,431 260,191 263,737 267,307 276,337 279,991 283,669
285,517 292,969 296,731 298,621 310,087 329,677 333,667 337,681 347,821 351,919
360,187 368,551 372,769 374,887 377,011 383,419 387,721 398,581 407,377 423,001
436,627 452,797 459,817 476,407 478,801 493,291 522,919 527,941 553,411 574,219
584,767 590,077 592,741 595,411 603,457 608,851 611,557 619,711 627,919 650,071
658,477 666,937 689,761 692,641 698,419 707,131 733,591 742,519 760,537 769,627
772,669 784,897 791,047 812,761 825,301 837,937 847,477 863,497 879,667 886,177
895,987 909,151 915,769 925,741 929,077 932,419 939,121 952,597 972,991 976,411
986,707 990,151 997,057 1,021,417 1,024,921 1,035,469 1,074,607 1,085,407 1,110,817 1,114,471
1,125,469 1,155,061 1,177,507 1,181,269 1,215,397 1,253,887 1,281,187 1,285,111 1,324,681 1,328,671
1,372,957 1,409,731 1,422,097 1,426,231 1,442,827 1,451,161 1,480,519 1,484,737 1,527,247 1,570,357
10-th cuban prime = 631
100-th cuban prime = 283,669
1,000-th cuban prime = 65,524,807
10,000-th cuban prime = 11,712,188,419
100,000-th cuban prime = 1,792,617,147,127
</pre>
=={{header|Julia}}==
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