A087090 Positive numbers n such that p=n^2+n+41 and p+2 are twin primes.
0, 5, 12, 15, 17, 20, 24, 35, 45, 50, 59, 75, 90, 92, 105, 110, 119, 120, 132, 134, 167, 174, 182, 222, 225, 230, 264, 269, 285, 320, 335, 339, 362, 365, 372, 390, 419, 434, 437, 455, 462, 470, 479, 495, 539, 540, 549, 572, 594, 705, 710, 714, 759, 785, 789
Offset: 1
Keywords
Examples
5 is in the sequence because 71 and 73 are twin primes.
Links
- Pierre CAMI and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 2028 terms from Cami)
Programs
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Mathematica
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 *) -
PARI
isok(n) = isprime(n^2+n+41) && isprime(n^2+n+43); \\ Michel Marcus, Oct 03 2013