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A076515
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Numbers k such that 1 + 3^k + 5^k is prime.
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4
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OFFSET
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1,2
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COMMENTS
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No more terms up to 75000 (previous range rechecked). All terms are multiples of 12: if k > 0 is not a multiple of 12, 1 + 3^k + 5^k is divisible by 3, 5 or 7. - Rick L. Shepherd, Aug 06 2017
Next term, if it exists, is greater than 10^6. - Jon Grantham, Jul 29 2023
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LINKS
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MAPLE
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MATHEMATICA
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Do[ If[ PrimeQ[1 + 3^n + 5^n], Print[n]], {n, 0, 3500, 2}]
Select[Range[0, 5000], PrimeQ[1+3^#+5^#]&] (* Harvey P. Dale, Mar 09 2012 *)
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PROG
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(PARI) lista(nn) = for(n=0, nn, if(ispseudoprime(1 + 3^n + 5^n), print1(n, ", "))); \\ Altug Alkan, Jan 25 2016
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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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EXTENSIONS
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STATUS
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approved
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