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A059801
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Numbers k such that 4^k - 3^k is prime.
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120
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2, 3, 7, 17, 59, 283, 311, 383, 499, 521, 541, 599, 1193, 1993, 2671, 7547, 24019, 46301, 48121, 68597, 91283, 131497, 148663, 184463, 341233
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OFFSET
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1,1
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COMMENTS
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Some of the larger entries may only correspond to probable primes.
The values corresponding to 1193 (719 digits) and 1993 (1200 digits) have been certified prime with Primo. - Rick L. Shepherd, Sep 10 2002
8 more terms found by Jean-Louis Charton during 2004 - 2006. Corresponding numbers of decimal digits are 14461, 27876, 28972, 41300, 54958, 79170, 89505, 111058, 205443. - Alexander Adamchuk, Dec 02 2006
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LINKS
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Table of n, a(n) for n=1..25.
Bogley, William A.; Williams, Gerald Efficient finite groups arising in the study of relative asphericity. Math. Z. 284, No. 1-2, 507-535 (2016).
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MATHEMATICA
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Select[Range[1000], PrimeQ[4^# - 3^#] &] (* Alonso del Arte, Nov 03 2011 *)
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PROG
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(PARI) select(vector(10^5, i, i), n->ispseudoprime(4^n-3^n)) \\ Charles R Greathouse IV, Feb 11 2011
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CROSSREFS
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Cf. A000043, A057468, A059802, etc., A129736, A129737.
Sequence in context: A176074 A281368 A330726 * A102226 A195530 A295509
Adjacent sequences: A059798 A059799 A059800 * A059802 A059803 A059804
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KEYWORD
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nonn,nice,hard
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AUTHOR
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Mike Oakes, Feb 23 2001
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STATUS
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approved
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