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 A242562 Primes p such that 1000p+1, 1000p+3, 1000p+7 and 1000p+9 are prime. 2

%I #4 May 20 2014 23:43:22

%S 13,1447,5527,28201,36217,75079,81157,95911,187423,188677,202327,

%T 210643,248077,263323,282589,283267,423043,466897,472597,478189,

%U 478603,631273,640261,695749,730111,736279,806929,808021,917641,964303,1018177,1026547,1064263,1108489,1150861

%N Primes p such that 1000p+1, 1000p+3, 1000p+7 and 1000p+9 are prime.

%e 130001, 130003, 130007 and 130009 are all prime. Thus 13 is a member of this sequence.

%o (Python)

%o import sympy

%o from sympy import isprime

%o from sympy import prime

%o {print(prime(n)) for n in range(1,10**5) if isprime(1000*prime(n)+1) and isprime(1000*prime(n)+3) and isprime(1000*prime(n)+7) and isprime(1000*prime(n)+9)}

%o (PARI) for(n=1,10^5,s=prime(n);if(ispseudoprime(1000*s+1) && ispseudoprime(1000*s+3) && ispseudoprime(1000*s+7) && ispseudoprime(1000*s+9),print(s)));

%Y Cf. A236042, A067267.

%K nonn

%O 1,1

%A _Derek Orr_, May 17 2014

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Last modified July 24 21:32 EDT 2024. Contains 374585 sequences. (Running on oeis4.)