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A198196
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Numbers k such that [V(4,1,k)/4] = floor(cosh(k log(sqrt(3)+2))/2) = A004526(A001075(k)) is a prime.
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1
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2, 3, 5, 7, 11, 13, 17, 19, 79, 151, 199, 233, 251, 317, 863, 971
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OFFSET
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1,1
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COMMENTS
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Further terms are 3049, 7451, 7487, 18869.
All terms must be primes. A117808 lists the corresponding primes floor(A001075(k)/2). Actually, the "floor" here and in the definition is only needed for the initial term 2, since no other even (thus composite) k can be in the sequence, and A001075(k) is even for odd k.
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LINKS
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PROG
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(PARI) q=2+quadgen(12); for(n=1, 1e9, ispseudoprime(real(q^n)\2) & print1(n", "))
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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