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 A224471 Numbers n such that 8^n - n is prime. 3
 1, 3, 37, 45, 597, 1131, 14203, 112539 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(8) > 41000. - Giovanni Resta, Apr 07 2013 a(9) > 2*10^5. - Robert Price, Jan 19 2014 LINKS MAPLE A224471:=proc(q) local n; for n from 1 to q do if isprime(8^n-n) then print(n); fi; od; end: A224471(15000); # Paolo P. Lava, Apr 19 2013 PROG (Java) import java.math.BigInteger; public class A224471 {   public static void main (String[] args) {     BigInteger b8 = BigInteger.valueOf(8);     BigInteger m = BigInteger.valueOf(64);     for(long n=1; ; n+=2) {         BigInteger b = b8.subtract(BigInteger.valueOf(n));         if (b.isProbablePrime(2)) {             if (b.isProbablePrime(80))                 System.out.printf("%d\n", n);         }         b8 = b8.multiply(m);     }   } } (PARI) forstep(n=1, 10^4, 2, if(ispseudoprime(8^n-n), print1(n, ", "))); /* Joerg Arndt, Apr 07 2013 */ CROSSREFS Cf. A048744, A058037, A057908, A058046, A058829, A224470, A224469, A224469. Sequence in context: A037000 A042333 A106103 * A286637 A106996 A338751 Adjacent sequences:  A224468 A224469 A224470 * A224472 A224473 A224474 KEYWORD nonn,hard,more AUTHOR Alex Ratushnyak, Apr 06 2013 EXTENSIONS a(7) from Giovanni Resta, Apr 07 2013 a(8) from Robert Price, Jan 19 2014 STATUS approved

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Last modified July 30 21:33 EDT 2021. Contains 346365 sequences. (Running on oeis4.)