A273088 a(n) is a multiple of 6 and a(n)-1 or a(n)+1 is an isolated (non-twin) prime number.

24, 36, 48, 54, 66, 78, 84, 90, 96, 114, 126, 132, 156, 162, 168, 174, 210, 222, 234, 252, 258, 264, 276, 294, 306, 318, 330, 336, 354, 360, 366, 372, 378, 384, 390, 396, 402, 408, 438, 444, 450, 456, 468, 480, 486, 492, 498, 504, 510, 540, 546, 558, 564, 576, 588, 594

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

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

Maple

select(t -> isprime(t-1) <> isprime(t+1), 6*[$1..200]);  # Robert Israel, Jul 10 2023

Mathematica

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 *)

Prog

(PARI) {
  forstep(n=6, 1000, 6,
    if((isprime(n-1)+isprime(n+1))==1,
      print1(n", ")
    )
  )
}

Crossrefs

Intersection of A008588 and A100317.

Sequence in context: A330880 A195008 A054775 * A334674 A067766 A376445

Adjacent sequences: A273085 A273086 A273087 * A273089 A273090 A273091

Keyword

nonn

Author

Dimitris Valianatos, May 14 2016

Status

approved