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A124490 Numbers n such that 2n-1, 4n-1, 6n-1, 8n-1, 10n-1, 12n-1 and 14n-1 are primes. 1
1447110, 2623005, 4095000, 4339335, 6975780, 9080190, 12382755, 19455975, 20322960, 30020760, 32261985, 54202995, 62014155, 63196350, 66383520, 71369340, 94571295, 121012185, 124225920, 162780660, 177109380, 196068180, 223888665, 303047745, 310143960 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..25.

MATHEMATICA

Select[3*5*7*Range[2000000], And @@ PrimeQ /@ ({2, 4, 6, 8, 10, 12, 14}*# - 1) &] (* Ray Chandler, Nov 21 2006 *)

pr7Q[n_]:=AllTrue[2*Range[7]n-1, PrimeQ]; Select[105*Range[3*10^6], pr7Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 17 2018 *)

CROSSREFS

Cf. A124485-A124492.

Sequence in context: A210629 A156621 A108841 * A124491 A205892 A186533

Adjacent sequences:  A124487 A124488 A124489 * A124491 A124492 A124493

KEYWORD

nonn

AUTHOR

Artur Jasinski, Nov 04 2006

EXTENSIONS

Extended by Ray Chandler, Nov 21 2006

More terms from Harvey P. Dale, May 17 2018

STATUS

approved

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Last modified November 27 07:28 EST 2021. Contains 349365 sequences. (Running on oeis4.)