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 A087090 Positive numbers n such that p=n^2+n+41 and p+2 are twin primes. 2

%I

%S 0,5,12,15,17,20,24,35,45,50,59,75,90,92,105,110,119,120,132,134,167,

%T 174,182,222,225,230,264,269,285,320,335,339,362,365,372,390,419,434,

%U 437,455,462,470,479,495,539,540,549,572,594,705,710,714,759,785,789

%N Positive numbers n such that p=n^2+n+41 and p+2 are twin primes.

%H Pierre CAMI and Charles R Greathouse IV, <a href="/A087090/b087090.txt">Table of n, a(n) for n = 1..10000</a> (first 2028 terms from Cami)

%e 5 is in the sequence because 71 and 73 are twin primes.

%t Select[Range[0,800],AllTrue[#^2 +#+{41,43},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, May 20 2016 *)

%o (PARI) isok(n) = isprime(n^2+n+41) && isprime(n^2+n+43); \\ _Michel Marcus_, Oct 03 2013

%Y Cf. A007634, A087091.

%K nonn

%O 1,2

%A _Zak Seidov_, Aug 08 2003

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Last modified September 17 16:17 EDT 2021. Contains 347487 sequences. (Running on oeis4.)