A273088 - OEIS

%I #13 Jul 10 2023 14:47:20

%S 24,36,48,54,66,78,84,90,96,114,126,132,156,162,168,174,210,222,234,

%T 252,258,264,276,294,306,318,330,336,354,360,366,372,378,384,390,396,

%U 402,408,438,444,450,456,468,480,486,492,498,504,510,540,546,558,564,576,588,594

%N a(n) is a multiple of 6 and a(n)-1 or a(n)+1 is an isolated (non-twin) prime number.

%H Robert Israel, <a href="/A273088/b273088.txt">Table of n, a(n) for n = 1..10000</a>

%e 66=6*11 and 66+1=67 are not twin primes, so 66 is a term.

%p select(t -> isprime(t-1) <> isprime(t+1), 6*[$1..200]);  # _Robert Israel_, Jul 10 2023

%t Select[6 Range@ 100, Total@ Boole@ Map[If[PrimeQ@ #, Count[Abs[# - {NextPrime[#, -1], NextPrime@ #}], k_ /; k == 2] < 1, False] &, {# - 1, # + 1}] > 0 &] (* _Michael De Vlieger_, May 15 2016 *)

%o (PARI) {

%o   forstep(n=6,1000,6,

%o     if((isprime(n-1)+isprime(n+1))==1,

%o       print1(n", ")

%o     )

%o   )

%o }

%Y Intersection of A008588 and A100317.

%K nonn

%O 1,1

%A _Dimitris Valianatos_, May 14 2016