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%I #11 Nov 06 2013 01:43:29
%S 4,6,8,10,12,14,18,22,24,26,34,38,46,58,60,62,74,82,86,94,106,118,122,
%T 134,142,146,158,166,178,194,202,206,214,218,226,254,262,274,278,298,
%U 302,314,326,334,346,358,362,382,386,394,398,422,446,454,458,466,478
%N Composite numbers n whose divisors less than or equal to sqrt(n) are consecutive, from 1 up to some number k.
%C The sequence consists of all numbers of the form 2p with p prime, along with 8, 12, 18, 24 and 60. See sketch of proof in A066522.
%H Reinhard Zumkeller, <a href="/A066664/b066664.txt">Table of n, a(n) for n = 1..1000</a>
%t a = {}; Do[ If[ !PrimeQ[n], k = Select[ Divisors[n], # <= Sqrt[n] &]; If[ Last[k] == Length[k], a = Append[a, n]]], {n, 1, 500} ]; a
%t dQ[n_]:=!PrimeQ[n]&&Union[Differences[Select[Divisors[n],#<=Sqrt[n]&]]] == {1}; Select[Range[500],dQ] (* _Harvey P. Dale_, Nov 06 2013 *)
%o (Haskell)
%o a066664 n = a066664_list !! (n-1)
%o a066664_list = filter ((== 0) . a010051) $ tail a066522_list
%o -- _Reinhard Zumkeller_, Nov 14 2011
%Y These are the composite members of A066522: intersection of A002808 and A066522.
%Y Subsequence: A100484.
%K nice,nonn,easy
%O 1,1
%A _Robert G. Wilson v_, Jan 07 2002
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