A243408 Primes p such that 10*p-1, 10*p-3, 10*p-7 and 10*p-9 are all prime.
2, 11, 83, 149, 347, 1301, 1607, 2531, 6299, 7727, 8273, 17117, 20183, 21737, 24371, 26669, 39227, 40277, 53951, 54917, 63347, 66359, 66467, 73637, 82217, 82373, 101537, 102251, 106397, 106871, 117203, 132971, 134033, 135221, 140237, 144701, 146141, 151433, 152597
Offset: 1
Keywords
Examples
2 is prime, 10*2-1 = 19 is prime, 10*2-3 = 17 is prime, 10*2-7 = 13 is prime, 10*2-9 = 11 is prime. Thus 2 is a member of this sequence.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
Select[ Range@ 153000,PrimeQ[#] && PrimeQ[10#-1] && PrimeQ[10#-3] && PrimeQ[10#-7] && PrimeQ[10#-9] &] (* Robert G. Wilson v, Jun 06 2014 *) Select[Prime[Range[15000]],AllTrue[10#-{1,3,7,9},PrimeQ]&] (* Harvey P. Dale, Aug 18 2024 *)
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PARI
for(n=1,10^5,if(ispseudoprime(10*prime(n)-1) && ispseudoprime(10*prime(n)-3) && ispseudoprime(10*prime(n)-7) && ispseudoprime(10*prime(n)-9),print1(prime(n),", ")))
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Python
import sympy from sympy import isprime from sympy import prime {print(prime(n),end=', ') for n in range(1,10**5) if isprime(10*prime(n)-1) and isprime(10*prime(n)-3) and isprime(10*prime(n)-7) and isprime(10*prime(n)-9)}
Comments