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A213073
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Numbers n such that (7^n - 4^n)/3 is prime.
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1
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2, 5, 11, 61, 619, 2879, 2957, 24371, 69247, 376463, 571199, 624803
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OFFSET
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1,1
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COMMENTS
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All terms are primes.
Next term > 10^6.
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LINKS
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MATHEMATICA
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k=7; Do[p=Prime[n]; f=(k^p-4^p)/(k-4); If[ PrimeQ[f], Print[p] ], {n, 1, 100}]
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PROG
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CROSSREFS
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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