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%I #7 Nov 21 2013 12:49:34
%S 10,20,28,42,55,66,88,99,110,130,156,170,187,204,238,255,272,304,342,
%T 368,391,414,460,483,506,551,580,609,638,696,725,754,783,812,868,930,
%U 962,999,1036,1073,1110,1184,1221,1258,1295,1332,1394,1435,1476,1558
%N Numbers n divisible by the least prime >= sqrt(n) but not by the largest prime <= sqrt(n).
%C Also: Numbers n divisible by the least prime >= sqrt(n) which are not in A001248 (primes squared) or A006094 (product of two consecutive primes). A subsequence of A157937.
%H Harvey P. Dale, <a href="/A157938/b157938.txt">Table of n, a(n) for n = 1..1000</a>
%F A157938 = A157936 \ A157942 = A157937 \ A006094, where A157937 = A157936 \ A001248.
%e a(1)=10 and a(2)=20 are divisible by 5 = nextprime(sqrt(10)) = nextprime(sqrt(20)) and neither a prime squared (as are 4 and 9) nor product of consecutive primes (as are 6 and 15).
%e 5,7,8 are not in this sequence, since not a multiple of 3=nextprime(sqrt(5))=nextprime(sqrt(8)).
%t dpQ[n_]:=Module[{srn=Sqrt[n],a,b},a=If[PrimeQ[srn],srn,NextPrime[ srn]];b=If[PrimeQ[srn],srn,NextPrime[srn,-1]]; Divisible[n,a]&& !Divisible[ n,b]]; Select[Range[2000],dpQ] (* _Harvey P. Dale_, Oct 10 2011 *)
%o (PARI) for( n=5,1999, n % nextprime(sqrtint(n-1)+1) & next; n % precprime(sqrtint(n)) & print1(n","))
%Y Cf. A157940.
%K nonn
%O 1,1
%A _M. F. Hasler_, Mar 10 2009