|
%I #22 Jan 08 2017 03:50:32
%S 5,10,12,15,19,20,23,25,26,30,33,34,35,36,40,45,47,49,50,53,54,55,56,
%T 60,61,62,65,67,68,70,72,75,78,80,82,85,87,88,89,90,91,95,96,100,101,
%U 103,104,105,110,111,114,115,117,118,120,121,122,124,125,127,129,130
%N Numbers n such that 6n + 5 is composite.
%C Conjecture: There exists no pair of primes (p, q > p^2) such that q - p^2 = 6*n - 4 (see A138479). - Philippe LALLOUET (philip.lallouet(AT)orange.fr), Mar 20 2008
%H G. C. Greubel, <a href="/A059324/b059324.txt">Table of n, a(n) for n = 1..5000</a>
%F a(n) = A046953(n-1) - 1.
%e a(3) = 12 because 6*12 + 5 = 77 is composite.
%t Select[Range[200],!PrimeQ[6#+5]&] (* _Harvey P. Dale_, Mar 13 2011 *)
%o (PARI) isok(n) = ! isprime(6*n+5); \\ _Michel Marcus_, Jan 06 2017
%Y Complement of A059325.
%Y Cf. A138479.
%K nonn,easy
%O 1,1
%A _Anton Joha_, Jan 26 2001
%E More terms from _Henry Bottomley_, Jan 29 2001
|
