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A210939 Nonprime nearest-neighbors of the primes. 1

%I #19 Oct 22 2022 14:02:28

%S 1,4,6,8,10,12,14,16,18,20,22,24,28,30,32,36,38,40,42,44,46,48,52,54,

%T 58,60,62,66,68,70,72,74,78,80,82,84,88,90,96,98,100,102,104,106,108,

%U 110,112,114,126,128,130,132,136,138,140,148,150,152,156

%N Nonprime nearest-neighbors of the primes.

%C Essentially the same as A147819. _R. J. Mathar_, Jun 25 2012

%t Select[Range[156], ! PrimeQ[#] && (PrimeQ[# - 1] || PrimeQ[# + 1]) &] (* _T. D. Noe_, Apr 18 2012 *)

%t Join[{1},Flatten[#+{-1,1}&/@Prime[Range[3,40]]]//Union] (* _Harvey P. Dale_, Oct 22 2022 *)

%Y Nonprimes in A045718.

%Y Cf. A000040, A018252, A134928, A134930, A210940.

%K nonn

%O 1,2

%A _Omar E. Pol_, Apr 17 2012

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Last modified July 27 13:23 EDT 2024. Contains 374647 sequences. (Running on oeis4.)