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A111215
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Numbers k such that 4k + 5 is prime.
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4
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0, 2, 3, 6, 8, 9, 12, 14, 17, 21, 23, 24, 26, 27, 33, 36, 38, 42, 44, 47, 48, 56, 57, 59, 63, 66, 68, 69, 72, 77, 78, 83, 86, 87, 92, 96, 98, 99, 101, 104, 107, 111, 113, 114, 126, 129, 134, 138, 141, 143, 147, 149, 152, 153, 159, 162, 164, 167, 168, 174, 176, 182, 188
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OFFSET
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1,2
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COMMENTS
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Solutions of the equation (4*k+5)' = 1, where k' is the arithmetic derivative of k. - Paolo P. Lava, Jan 03 2013
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LINKS
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Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) = A005098(n) - 1. - Daniel Starodubtsev, Feb 10 2020
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EXAMPLE
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If k=99 then 4k + 5 = 401 (prime).
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MATHEMATICA
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Select[Range[0, 200], PrimeQ[4#+5]&] (* Harvey P. Dale, Dec 07 2013 *)
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PROG
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(MAGMA) [n: n in [0..200] | IsPrime(4*n+5)]; - Vincenzo Librandi, Nov 13 2010
(PARI) is(n)=isprime(4*n+5) \\ Charles R Greathouse IV, Aug 31 2015
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CROSSREFS
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Cf. A005098, A095278.
Sequence in context: A135768 A287659 A047244 * A099381 A289943 A089437
Adjacent sequences: A111212 A111213 A111214 * A111216 A111217 A111218
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KEYWORD
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nonn,easy
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AUTHOR
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Parthasarathy Nambi, Oct 24 2005
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STATUS
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approved
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