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A273088 a(n) is a multiple of 6 and a(n)-1 or a(n)+1 is an isolated (non-twin) prime number. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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 A306776
KEYWORD
nonn
AUTHOR
Dimitris Valianatos, May 14 2016
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)