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A289353 Primes p such that (p,p+4) is a pair of cousin primes and p == 7 (mod 10). 2

%I

%S 7,37,67,97,127,277,307,397,457,487,757,877,907,937,967,1087,1297,

%T 1447,1567,1597,1867,2137,2347,2377,2437,2617,2707,2797,2857,3037,

%U 3187,3217,3457,3697,3847,3877,3907,4447,5077,5167,5227,5347,5437,5527,5647,5737,5857,6007,6217,6547,6577

%N Primes p such that (p,p+4) is a pair of cousin primes and p == 7 (mod 10).

%C For cousin primes (p,p+4) such that p == 9 (mod 10), see A074822.

%C Members of A023200 with a last digit of 7. - _Iain Fox_, Dec 22 2017

%H Muniru A Asiru, <a href="/A289353/b289353.txt">Table of n, a(n) for n = 1..10000</a>

%e The pair of cousin prime (3,7) is not a member since 3 mod 10 = 3.

%e For p = 97, we get that (97,101) is a cousin prime pair and 97 == 7 (mod 10).

%p a:={}: for i from 1 to 1500 do if isprime(ithprime(i)+4) and ithprime(i) mod 10 = 7 then a:={op(a),ithprime(i)}: fi: od: a; # _Muniru A Asiru_, Aug 04 2017

%t Select[10 Range[0, 660] + 7, PrimeQ[#] && PrimeQ[# + 4] &] (* _Robert G. Wilson v_, Dec 11 2017 *)

%o (GAP)

%o P:=Filtered([1..10000],IsPrime);;

%o P1:=List(Filtered(Filtered(List([1..Length(P)-1],n->[P[n],P[n+1]]),i->i[2]-i[1]=4),j->j[1] mod 5 =2),k->k[1]);

%o (PARI) isok(p) = isprime(p) && isprime(p+4) && ((p % 10) == 7); \\ _Michel Marcus_, Jul 03 2017

%o (PARI) is(n)=n%30==7 && isprime(n+4) && isprime(n) \\ _Charles R Greathouse IV_, Jul 13 2017

%Y Cf. A001223, A001359, A023200, A046132, A074822, A160440.

%K nonn

%O 1,1

%A _Muniru A Asiru_, Jul 03 2017

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Last modified June 25 03:53 EDT 2021. Contains 345449 sequences. (Running on oeis4.)