cp's OEIS Frontend

A227063 Prime in the middle of a list of 7 consecutive primes such that each of them is a member of a twin pair.

%I A227063 #39 Mar 06 2025 01:52:53
%S A227063 11,9433,9437,62983,62987,72229,72251,392269,392279,495589,495611,
%T A227063 663583,663587,909301,909317,909319,909329,1006309,1006331,1138393,
%U A227063 1138409,1159201,1159229,1173553,1173581,1322161,1322171,2144491
%N A227063 Prime in the middle of a list of 7 consecutive primes such that each of them is a member of a twin pair.
%C A227063 This is roughly a search for at least three successive zeros in A048614.
%H A227063 Robert Israel, <a href="/A227063/b227063.txt">Table of n, a(n) for n = 1..1000</a>
%e A227063 The twin prime 9433 is in the sequence because it is in the middle of the list of 7 successive primes 9419, 9421, 9431, 9433, 9437, 9439, 9461, of which each is a member of a twin prime pair.
%p A227063 L:= [seq(ithprime(i),i=1..8)]: Flags:= [false,true$6]: count:= 0: R:= NULL:
%p A227063 while count < 40 do
%p A227063   L:= [seq(L[i],i=2..8),nextprime(L[8])];
%p A227063   Flags:= [seq(Flags[i],i=2..7),(L[7]-L[6]=2) or (L[8]-L[7]=2)];
%p A227063   if Flags = [true$7] then R:= R, L[4]; count:= count+1;  fi
%p A227063 od:
%p A227063 R; # _Robert Israel_, Mar 05 2025
%t A227063 tp7Q[lst_]:=Total[If[PrimeQ[#+2]||PrimeQ[#-2],1,0]&/@lst]==7; Select[Partition[Prime[ Range[ 160000]],7,1],tp7Q][[;;,4]] (* _Harvey P. Dale_, Oct 22 2023 *)
%Y A227063 Cf. A001097, A048614.
%K A227063 nonn
%O A227063 1,1
%A A227063 _Irina Gerasimova_, Jun 30 2013