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A002970 Numbers n such that 4*n^2 + 9 is prime.
(Formerly M3248)
6

%I M3248

%S 1,4,5,10,16,19,20,26,29,31,35,41,44,49,50,55,56,59,70,71,80,85,94,95,

%T 100,101,106,109,110,121,149,154,160,166,175,179,184,190,191,200,205,

%U 206,211,224,236,241,245,251,256,265,269,271,284,286,289,299,304,314

%N Numbers n such that 4*n^2 + 9 is prime.

%D E. Kogbetliantz and A. Krikorian, Handbook of First Complex Prime Numbers, Gordon and Breach, NY, 1971, p. 1.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H T. D. Noe, <a href="/A002970/b002970.txt">Table of n, a(n) for n = 1..1000</a>

%H E. Kogbetliantz and A. Krikorian <a href="/A002970/a002970.pdf">Handbook of First Complex Prime Numbers</a>, Gordon and Breach, NY, 1971 [Annotated scans of a few pages]

%t Select[Range[350], PrimeQ[4 #^2 + 9] &] (* _Vincenzo Librandi_, Mar 19 2014 *)

%o (Magma)[n: n in [0..600]|IsPrime(4*n^2+9)]; // _Vincenzo Librandi_, Nov 21 2010

%o (PARI) is(n)=isprime(4*n^2+9) \\ _Charles R Greathouse IV_, Feb 17 2017

%K nonn,easy

%O 1,2

%A _N. J. A. Sloane_.

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Last modified January 29 22:20 EST 2023. Contains 359931 sequences. (Running on oeis4.)