A094383 Primes p such that d>0 exists and p-d, p-2*d and p-3*d are also primes.
23, 29, 41, 43, 53, 59, 79, 83, 97, 101, 103, 107, 113, 127, 131, 139, 149, 151, 157, 163, 167, 173, 181, 191, 193, 197, 199, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 281, 283, 293, 307, 311, 313, 317, 331, 347, 349, 353, 359, 367, 373, 383
Offset: 1
Keywords
Examples
59=prime(17) -> 59-6=53=prime(16) -> 53-6=47=prime(15) -> 47-6=41=prime(13), therefore 59 is a term; also 59 -> 59-18=41=prime(13) -> 41-18=23=prime(9) -> 23-18=5=prime(3).
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
prms = 3; fQ[p_] := Module[{d = 1}, While[prms*d < p && Union[PrimeQ[p - Range[prms]*d]] != {True}, d++]; prms*d < p]; Select[Prime[Range[2, PrimePi[383]]], fQ] (* T. D. Noe, Sep 08 2012 *) -
PARI
is(n)=my(t); forprime(p=2,n-6,if((n-p)%3==0 && isprime((t=(n-p)/3)+p) && isprime(2*t+p) && isprime(n), return(1))); 0 \\ Charles R Greathouse IV, Sep 10 2014
Comments