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%I #10 Sep 08 2022 08:46:04
%S 163,811,1423,1783,2179,3079,3583,9739,11503,13411,14419,17659,22483,
%T 25111,26479,27883,42139,49411,55243,57259,70111,72379,77023,79399,
%U 86743,97039,116443,119359,125299,140779,181603,188911,207811
%N Primes of the form 2*n^2 + 42*n + 19.
%C Conjecture: 2^a(n)-1 is not prime; in other words, these primes are included in A054723.
%C 2*a(n) + 403 is a square. - _Vincenzo Librandi_, Apr 10 2015
%H Vincenzo Librandi, <a href="/A221903/b221903.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Table[2 n^2 + 42 n + 19, {n, 500}], PrimeQ]
%o (Magma) [a: n in [1..500] | IsPrime(a) where a is 2*n^2 + 42*n + 19];
%Y Cf. Primes of the form 2*n^2+2*(2*k+3)*n+(2*k+1): A176549 (k=0), A154577 (k=2), A154592 (k=3), A154601 (k=4), A217494 (k=7), this sequence (k=9), A217495 (k=10), A217496 (k=11), A217497 (k=12), A217498 (k=13), A217499 (k=16), A217500 (k=17), A217501 (k=18), A217620 (k=19), A217621 (k=21).
%Y Cf. A054723.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Feb 01 2013
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