%I #7 Sep 21 2024 13:23:42

%S 1,4,6,8,9,10,12,14,15,20,21,22,24,25,26,27,32,33,34,35,36,42,44,45,

%T 46,48,49,50,51,52,54,55,56,57,60,62,63,64,65,66,68,69,70,74,75,76,77,

%U 80,84,85,86,87,90,91,92,93,94,102,104,105,110,111,112,114,115,116,117,118

%N Numbers n such that nextprime(3*n)<3*nextprime(n) (if p is prime then nextprime(p)=p).

%H Iain Fox, <a href="/A117097/b117097.txt">Table of n, a(n) for n = 1..10000</a>

%e nextprime(3*4)=13 and nextprime(3)*nextprime(4)=3*5=15 then 4 is member because 13<15

%t np[n_]:=If[PrimeQ[n],n,NextPrime[n]]; Select[Range[150],np[3*#]<(3np[#])&] (* _Harvey P. Dale_, Sep 21 2024 *)

%o (PARI) for(i=1,150,if(nextprime(3*i)<nextprime(3)*nextprime(i),print1(i,",")))

%K easy,nonn,changed

%O 1,2

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