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A173553
Numbers n such that 5+38*n^2 is not a prime.
4
5, 10, 14, 15, 18, 20, 25, 27, 28, 30, 35, 40, 41, 42, 43, 44, 45, 46, 47, 50, 51, 52, 55, 57, 60, 65, 67, 68, 69, 70, 72, 73, 74, 75, 76, 80, 81, 85, 87, 89, 90, 91, 92, 94, 95, 97, 98, 100, 101, 102, 103, 105, 107, 109, 110, 111, 112, 113, 115, 117, 120, 121, 124, 125, 126, 127
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[150], !PrimeQ[5 + 38 #^2]&] (* Vincenzo Librandi, Apr 05 2013 *)
PROG
(Magma) [n: n in [1..150] | not IsPrime(5 + 38*n^2)]; // Vincenzo Librandi, Apr 05 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 21 2010
EXTENSIONS
Entries recomputed by Alonso Del Arte and N. J. A. Sloane, Jun 18 2010
STATUS
approved