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A241403
Numbers n such that (n^2 + 2)/3 is not prime.
1
0, 1, 3, 4, 5, 6, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 36, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84
OFFSET
1,3
LINKS
EXAMPLE
4 is in the sequence because (4^2+2)/3 = 2*3.
MATHEMATICA
Select[Range[0, 200], ! PrimeQ[(#^2 + 2)/3] &]
PROG
(Magma) [0, 1, 3] cat [ n: n in [2..90] | not IsPrime((n^2+2) div 3) ];
CROSSREFS
Complement of A240878.
Sequence in context: A039132 A187970 A122488 * A287727 A298606 A039095
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 21 2014
STATUS
approved