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A137920 Numbers k such that 24*k-1 and 24*k+1 are twin primes. 4
3, 8, 10, 13, 18, 25, 43, 48, 55, 62, 67, 78, 87, 88, 108, 112, 113, 125, 130, 132, 140, 147, 153, 157, 172, 178, 200, 207, 218, 220, 230, 235, 245, 265, 273, 283, 290, 297, 312, 315, 337, 343, 375, 385, 393, 405, 407, 417, 428, 465, 473, 493, 503, 510, 542 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MAPLE

select(t -> isprime(24*t-1) and isprime(24*t+1), [$1..1000]); # Robert Israel, Feb 11 2018

MATHEMATICA

q=24; lst={}; Do[r=n*q; If[PrimeQ[r-1]&&PrimeQ[r+1], AppendTo[lst, n]], {n, 1, 10^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 07 2008 *)

Select[Range[600], PrimeQ[24 # - 1] && PrimeQ[24 # + 1] &] (* Vincenzo Librandi, Feb 12 2018 *)

PROG

(PARI) isok(k) = isprime(24*k-1) && isprime(24*k+1); \\ Michel Marcus, Feb 12 2018

(MAGMA) [n: n in [1..600] | IsPrime(24*n+1) and IsPrime(24*n-1)] // Vincenzo Librandi, Feb 12 2018

CROSSREFS

Cf. A124519, A135023, A135368, A137876, A137877, A137919.

Sequence in context: A064147 A287573 A122529 * A263005 A126581 A003038

Adjacent sequences:  A137917 A137918 A137919 * A137921 A137922 A137923

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 23 2008

STATUS

approved

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Last modified July 24 14:45 EDT 2021. Contains 346273 sequences. (Running on oeis4.)