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Squarefree numbers having exactly two prime gaps.
7

%I #9 Apr 10 2021 05:52:38

%S 110,130,170,182,190,230,238,266,273,290,310,322,357,370,374,399,406,

%T 410,418,430,434,470,483,494,506,518,530,546,561,574,590,598,602,609,

%U 610,627,638,651,658,670,682,710,714,730,741,742,754,759,777,782,790

%N Squarefree numbers having exactly two prime gaps.

%H Amiram Eldar, <a href="/A073488/b073488.txt">Table of n, a(n) for n = 1..10000</a>

%F A073484(a(n)) = 2.

%e 1430 is a term, as 1430 = 2*5*11*13 with two gaps: between 2 and 5 and between 5 and 11.

%t q[n_] := SequenceCount[FactorInteger[n][[;; , 1]], {p1_, p2_} /; p2 != NextPrime[p1], Overlaps -> True] == 2; Select[Range[800], SquareFreeQ[#] && q[#] &] (* _Amiram Eldar_, Apr 10 2021 *)

%Y Cf. A005117, A073486, A073487, A073489, A073494.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Aug 03 2002