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A117921 Primes of the form (2^k - 1)^3 - 2. 1

%I #13 Oct 22 2016 10:23:43

%S 3373,29789,133432829,8577357821,281462092005373

%N Primes of the form (2^k - 1)^3 - 2.

%C Exponent-3 analog of what for exponent 2 is A091516 Carol primes (2^n-1)^2 - 2 = 4^n - 2^{n+1} - 1. Hence this is a type of "near-cube primes."

%H Charles R Greathouse IV, <a href="/A117921/b117921.txt">Table of n, a(n) for n = 1..10</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Near-SquarePrime.html">Near-Square Prime.</a>

%F A098878 INTERSECTION A000040. {(2^k - 1)^3 - 2 iff prime}.

%e a(1) = (2^4 - 1)^3 - 2 = 3373 is prime.

%e a(2) = (2^5 - 1)^3 - 2 = 29789 is prime.

%e a(3) = (2^9 - 1)^3 - 2 = 133432829 is prime.

%e a(4) = (2^11 - 1)^3 - 2 = 8577357821 is prime.

%t Select[(2^Range[20]-1)^3-2,PrimeQ] (* _Harvey P. Dale_, Oct 22 2016 *)

%Y Cf. A091516, A091515, A098878, A091514.

%K nonn

%O 1,1

%A _Jonathan Vos Post_, May 03 2006

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Last modified May 1 16:12 EDT 2024. Contains 372175 sequences. (Running on oeis4.)