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A058781 Numbers k such that k^2 * 2^k - 1 is prime. 10

%I #14 Nov 07 2023 03:22:27

%S 3,7,25,41,45,63,83,131,147,175,425,449,469,651,1345,1839,1883,1913,

%T 2177,2551,2907,3675,6071,11743,14641,38685,40857,47761,97243

%N Numbers k such that k^2 * 2^k - 1 is prime.

%C If it exists, a(30) > 200000. - _Hugo Pfoertner_, Nov 07 2023

%H Steven Harvey, <a href="http://harvey563.tripod.com/GeneralizedHyperWoodall.txt">Generalized HyperWoodall Primes</a>

%t Do[ If[ PrimeQ[ n^2*2^n - 1 ], Print[n] ], {n, 1, 5000} ]

%o (PARI) is(n)=ispseudoprime(n^2*2^n-1) \\ _Charles R Greathouse IV_, May 22 2017

%Y Cf. A058780.

%K nonn

%O 1,1

%A _Robert G. Wilson v_, Jan 02 2001

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

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Last modified June 8 12:22 EDT 2024. Contains 373217 sequences. (Running on oeis4.)