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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..59.

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

Cf. A060461, A045751.

Sequence in context: A091898 A061365 A102107 * A176686 A007935 A076055

Adjacent sequences:  A217704 A217705 A217706 * A217708 A217709 A217710

KEYWORD

nonn,easy

AUTHOR

Jayanta Basu, Mar 20 2013

STATUS

approved

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Last modified September 20 12:43 EDT 2019. Contains 327238 sequences. (Running on oeis4.)