A247151 - OEIS

%I #27 Sep 08 2022 08:46:09

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,

%T 26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,46,47,48,49,

%U 50,51,52,55,56,57,59,61,62,64,65,66,69,70,71,73,78,80,82,83,84,85,88,90

%N Numbers n such that abs(36*n^2 - 810*n + 2753) is prime.

%C For 5, 6,...,18, the expression is negative, so the absolute value must be considered to get a (positive) prime. Thereafter, for 45, 53, 54, 58, 60, 63, 67, 68, 72, 74,... the values are composite. - _M. F. Hasler_, Jan 18 2015

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Prime-GeneratingPolynomial.html">Prime-Generating Polynomial</a>

%t Select[Range[0, 100], PrimeQ[(36 #^2 - 810 # + 2753)] &]

%o (Magma) [n: n in [0..100] | IsPrime(36*n^2-810*n+2753)];

%o (PARI) for(n=0,999,isprime(abs(36*n^2-810*n+2753))&&print1(n","))

%Y Cf. A050268 (associated primes).

%K nonn,easy

%O 1,3

%A _Vincenzo Librandi_, Nov 21 2014

%E Corrected by _M. F. Hasler_, Jan 18 2015