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A366171
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Integers k such that (2^(k+3)-2^k-1)/5 is prime.
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0
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3, 7, 19, 27, 31, 39, 151, 199, 451, 2371, 2511, 7859, 103819
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OFFSET
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1,1
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COMMENTS
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If p=(2^(k+3)-2^k-1)/5 is prime, then 2^(k+2)*p is a strongly 2-near perfect number.
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LINKS
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Vedant Aryan, Dev Madhavani, Savan Parikh, Ingrid Slattery, and Joshua Zelinsky, On 2-Near Perfect Numbers, arXiv:2310.01305 [math.NT], 2023. See p. 15.
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PROG
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(PARI) isok(k) = my(x=(2^(k+3)-2^k-1)/5); (denominator(x)==1) && ispseudoprime(x);
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CROSSREFS
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Cf. A366172 (strongly 2-near perfect numbers).
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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