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A154862
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Nonprimes of the form prime(prime(n)) - 2*n.
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0
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1, 1, 9, 21, 45, 51, 65, 105, 133, 153, 209, 243, 247, 325, 357, 385, 413, 459, 495, 531, 675, 707, 729, 789, 805, 845, 891, 913, 951, 981, 1003, 1067, 1083, 1111, 1125, 1203, 1313, 1335, 1347, 1369, 1395, 1417, 1557, 1625, 1703, 1725, 1935, 1967, 2133, 2211
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OFFSET
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1,3
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LINKS
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Table of n, a(n) for n=1..50.
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MAPLE
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for n from 1 to 100 do p := ithprime(ithprime(n))-2*n ; if not isprime(p) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Jan 18 2009
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MATHEMATICA
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Select[Table[Prime[Prime[n]] - 2 n, {n, 80}], ! PrimeQ[#] &] (* Vincenzo Librandi, Jan 08 2019 *)
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PROG
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(Magma) [a: n in [1..100] | not IsPrime(a) where a is NthPrime(NthPrime(n)) -2*n]; // Vincenzo Librandi, Jan 08 2019
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CROSSREFS
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Cf. A006450, A141468.
Sequence in context: A053476 A110680 A163205 * A350632 A020137 A231570
Adjacent sequences: A154859 A154860 A154861 * A154863 A154864 A154865
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KEYWORD
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nonn
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AUTHOR
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Juri-Stepan Gerasimov, Jan 16 2009
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EXTENSIONS
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35 replaced with 45 and 645 replaced with 675 by R. J. Mathar, Jan 18 2009
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STATUS
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approved
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