A124490 Numbers n such that 2n-1, 4n-1, 6n-1, 8n-1, 10n-1, 12n-1 and 14n-1 are primes.

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

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