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Numbers n such that nextprime(7*n)>7*nextprime(n) (if p is prime then nextprime(p)=p).
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%I #5 Nov 21 2013 12:48:57

%S 2,3,5,7,11,13,17,19,23,29,31,37,41,42,43,46,47,53,59,61,67,71,73,79,

%T 83,89,97,101,103,107,109,113,127,131,137,139,149

%N Numbers n such that nextprime(7*n)>7*nextprime(n) (if p is prime then nextprime(p)=p).

%e nextprime(7*2)=17 and nextprime(7)*nextprime(2)=7*2=14 then 2 is member because 17>14

%t nPrime[x_]:=If[PrimeQ[x],x,NextPrime[x]]; Select[Range[150],nPrime[7#]> 7nPrime[#]&] (* _Harvey P. Dale_, Feb 16 2012 *)

%o (PARI) for(i=1,150,if(nextprime(7*i)>nextprime(7)*nextprime(i),print1(i,",")))

%K easy,nonn

%O 1,1

%A Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 18 2006