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A124487 Numbers k such that 2*k-1, 4*k-1, 6*k-1 and 8*k-1 are primes. 2

%I #12 Mar 27 2020 09:01:44

%S 3,45,705,945,5295,5775,5955,6450,8580,9945,11175,12120,13095,18000,

%T 18525,18690,19710,22440,22785,24960,30390,33780,34335,37665,41790,

%U 44460,52185,54180,56175,57300,63570,66990,67515,67725,73335,74700

%N Numbers k such that 2*k-1, 4*k-1, 6*k-1 and 8*k-1 are primes.

%H Amiram Eldar, <a href="/A124487/b124487.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[80000], And @@ PrimeQ /@ ({2, 4, 6, 8}*# - 1) &] (* _Ray Chandler_, Nov 21 2006 *)

%Y Cf. A124485-A124492.

%K nonn

%O 1,1

%A _Artur Jasinski_, Nov 04 2006

%E Extended by _Ray Chandler_, Nov 21 2006

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Last modified April 16 01:01 EDT 2024. Contains 371696 sequences. (Running on oeis4.)