

A007591


Numbers n such that n^2+4 is prime.
(Formerly M2416)


19



1, 3, 5, 7, 13, 15, 17, 27, 33, 35, 37, 45, 47, 57, 65, 67, 73, 85, 87, 95, 97, 103, 115, 117, 125, 135, 137, 147, 155, 163, 167, 177, 183, 193, 203, 207, 215, 217, 233, 235, 243, 245, 253, 255, 265, 267, 275, 277, 287, 293, 303, 307, 313, 317, 347, 357, 373, 375
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


REFERENCES

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


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, NearSquare Prime


MATHEMATICA

lst={}; Do[If[PrimeQ[n^2+4], Print[n]; AppendTo[lst, n]], {n, 10^5}]; lst [From Vladimir Joseph Stephan Orlovsky, Aug 21 2008]
Select[Range[0, 400], PrimeQ[#^2 + 4] &] (* Vincenzo Librandi, Sep 25 2012 *)


PROG

(MAGMA) [n: n in [0..400]  IsPrime(n^2+4)]; [From Vincenzo Librandi, Nov 18 2010]
(PARI) select(n>isprime(n^4+4), vector(500, n, 2*n1)) \\ Charles R Greathouse IV, Sep 25 2012


CROSSREFS

Sequence in context: A092793 A024909 A063241 * A097687 A032911 A157834
Adjacent sequences: A007588 A007589 A007590 * A007592 A007593 A007594


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, R. K. Guy.


STATUS

approved



