27 lines
763 B
Java
27 lines
763 B
Java
import java.math.BigInteger;
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public final class RepunitPrimes {
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public static void main(String[] aArgs) {
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final int limit = 2_700;
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System.out.println("Repunit primes, up to " + limit + " digits, in:");
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for ( int base = 2; base <= 16; base++ ) {
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System.out.print(String.format("%s%2s%s", "Base ", base, ": "));
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String repunit = "";
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while ( repunit.length() < limit ) {
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repunit += "1";
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if ( BigInteger.valueOf(repunit.length()).isProbablePrime(CERTAINTY_LEVEL) ) {
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BigInteger value = new BigInteger(repunit, base);
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if ( value.isProbablePrime(CERTAINTY_LEVEL) ) {
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System.out.print(repunit.length() + " ");
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}
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}
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}
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System.out.println();
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}
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}
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private static final int CERTAINTY_LEVEL = 20;
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}
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