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A124415 Numbers k such that 2*k+1, 4*k+1, 8*k+1, 16*k+1, 32*k+1, 64*k+1 and 128*k+1 are primes. 2

%I #13 Mar 25 2020 06:50:42

%S 8325,82950,884220,1120470,3441690,5627895,5765505,7664745,7757430,

%T 8555040,10739505,11891625,15514860,15623475,18268455,22631970,

%U 24833775,27373410,29342895,31286970,31577205,50077455,51541035,58646520

%N Numbers k such that 2*k+1, 4*k+1, 8*k+1, 16*k+1, 32*k+1, 64*k+1 and 128*k+1 are primes.

%H Amiram Eldar, <a href="/A124415/b124415.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[15*Range[4000000], And @@ PrimeQ /@ ({2, 4, 8, 16, 32, 64, 128}*# + 1) &] (* _Ray Chandler_, Nov 21 2006 *)

%Y Cf. A005097, A123998, A124041, A124412-A124417.

%K nonn

%O 1,1

%A _Artur Jasinski_, Nov 02 2006

%E Corrected and extended by _Ray Chandler_, Nov 21 2006

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Last modified June 19 18:58 EDT 2024. Contains 373507 sequences. (Running on oeis4.)