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Numbers n such that A034693(n) = 3: 3n + 1 is prime, but neither n + 1 nor 2n + 1.
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%I #20 May 13 2018 19:53:22

%S 24,32,34,64,76,80,92,94,104,110,122,124,132,144,152,154,182,202,206,

%T 214,220,236,242,244,246,252,274,286,294,302,322,332,340,344,356,362,

%U 364,374,376,390,412,416,434,474,482,484,494,496

%N Numbers n such that A034693(n) = 3: 3n + 1 is prime, but neither n + 1 nor 2n + 1.

%H Michael De Vlieger, <a href="/A034782/b034782.txt">Table of n, a(n) for n = 1..10000</a>

%t Position[#, 3] &@ Table[k = 1; While[! PrimeQ[k n + 1], k++]; k, {n, 500}] // Flatten (* _Michael De Vlieger_, Mar 02 2017 *)

%o (PARI) is(n)=!isprime(n+1)&&!isprime(2*n+1)&&isprime(3*n+1) \\ _M. F. Hasler_, May 13 2018

%Y Cf. A034693, A034694.

%K nonn

%O 1,1

%A _Labos Elemer_

%E Corrected by _R. J. Mathar_, Jul 26 2015

%E Name edited by _M. F. Hasler_, May 13 2018