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A217707
Numbers n such that both 4*n-1 and 4*n+1 are composite.
0
14, 16, 19, 23, 29, 30, 31, 36, 40, 44, 46, 47, 51, 52, 54, 55, 59, 61, 62, 65, 72, 74, 75, 76, 80, 81, 82, 85, 86, 89, 91, 94, 98, 101, 103, 104, 106, 107, 109, 113, 118, 119, 121, 124, 128, 129, 132, 133, 134, 136, 138, 140, 145, 146, 149, 151, 156, 157, 159
OFFSET
1,1
MATHEMATICA
Select[Range[200], ! PrimeQ[4 # - 1] && ! PrimeQ[4 # + 1] &]
Select[Range[200], AllTrue[4#+{1, -1}, CompositeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 11 2015 *)
CROSSREFS
Sequence in context: A061365 A327822 A102107 * A176686 A007935 A076055
KEYWORD
nonn,easy
AUTHOR
Jayanta Basu, Mar 20 2013
STATUS
approved