A214000 - OEIS

%I #4 Jul 05 2012 11:54:56

%S 0,0,1,2,0,3,0,3,0,2,4,2,0,0,4,2,1,1,1,0,0,5,2,1,3,0,5,0,8,5,0,3,3,1,

%T 3,9,1,2,1,0,3,3,0,2,6,12,14,2,1,0,2,4,8,0,13,0,0,10,5,5,7,0,4,2,1,0,

%U 3,1,5,7,0,2,0,1,9,3,13,3,4,5,0,7,5,4,2

%N Number of twin prime pairs between two consecutive prime triples (p, p+2, p+6).

%e a(6)= 3 because between the 6th and 7th prime triples there are 3 twin prime pairs : (107,109,113), (137,139), (149,151), (179,181), (191,193,197).

%p with(numtheory):T:=array(1..1000):k:=1:for n from 1 to 4000 do:p:=ithprime(n):if type(p+2,prime)=true and type(p+6,prime) = true then T[k]:=p:T[k+1]:=p+6:k:=k+2:else fi:od:for m from 2 by 2 to k-2 do: p1:= T[m]:p2:=T[m+1]:i:=0:for q from p1+1 to p2-1 do:if type(q,prime)=true and type(q+2,prime) = true and q+2 <>p2 then i:=i+1:else fi:od: printf(`%d, `,i):od:

%Y Cf. A181747, A022004, A048614, A022004, A204100.

%K nonn

%O 1,4

%A _Michel Lagneau_, Jun 30 2012