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Primes of the form 8*k^2 + 1.
3

%I #20 Sep 08 2022 08:45:12

%S 73,1153,1801,2593,3529,8713,10369,18433,20809,34849,48673,52489,

%T 69193,83233,103969,115201,139393,180001,187273,209953,259201,267913,

%U 362953,405001,415873,426889,438049,449353,472393,484129,508033,622729,636193

%N Primes of the form 8*k^2 + 1.

%H Daniel Starodubtsev, <a href="/A090685/b090685.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[8 Range[300]^2+1,PrimeQ] (* _Harvey P. Dale_, Apr 02 2011 *)

%o (PARI) A090685(n) = { for(x=1,n, y = 8*x^2+1; if(isprime(y),print1(y",")) ) }

%o (Magma) [ a: n in [0..350] | IsPrime(a) where a is 8*n^2+1 ]; // _Vincenzo Librandi_, Apr 04 2011

%Y Cf. A188549.

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Dec 18 2003