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A060231 Smaller of twin primes whose middle term is a multiple of A002110(5)=2310. 5

%I

%S 2309,9239,11549,25409,34649,43889,55439,78539,92399,110879,117809,

%T 133979,152459,168629,180179,224069,226379,230999,244859,251789,

%U 267959,270269,284129,297989,300299,309539,314159,316469,330329,376529,390389

%N Smaller of twin primes whose middle term is a multiple of A002110(5)=2310.

%C Number of terms less than 10^k: 0, 0, 0, 0, 2, 9, 66, 422, 3255, ... - _Muniru A Asiru_, Jan 29 2018

%H Muniru A Asiru, <a href="/A060231/b060231.txt">Table of n, a(n) for n = 1..1000</a>

%e For the pair {9239,9241} (9239+9241)/2 = 4*2310.

%p select(n->isprime(n) and isprime(n+2), [seq(2310*k-1, k=1..10^3)]); # _Muniru A Asiru_, Jan 29 2018

%t Select[2310*Range[200],And@@PrimeQ[#+{1,-1}]&]-1 (* _Harvey P. Dale_, Aug 23 2013 *)

%o (GAP) P:=Filtered([1..10^5], IsPrime);;

%o P1:=List(Filtered(Filtered(List([1..Length(P)-1], n -> [P[n],P[n+1]]),i -> i[2]-i[1] = 2), j -> (j[1]+j[2]) mod 2310 = 0), k -> k[1]); # _Muniru A Asiru_, Jan 29 2018

%o (PARI) is(n)=(n+1)%2310==0 && isprime(n+2) && isprime(n) \\ _Charles R Greathouse IV_, Jan 30 2018

%Y Cf. A001359, A002110, A060229, A060230.

%K nonn

%O 1,1

%A _Labos Elemer_, Mar 21 2001

%E Minor edits by _Ray Chandler_, Apr 02 2009

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Last modified January 25 05:31 EST 2021. Contains 340416 sequences. (Running on oeis4.)