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 A105760 Numbers n such that 2n+7 is prime. 26
 0, 2, 3, 5, 6, 8, 11, 12, 15, 17, 18, 20, 23, 26, 27, 30, 32, 33, 36, 38, 41, 45, 47, 48, 50, 51, 53, 60, 62, 65, 66, 71, 72, 75, 78, 80, 83, 86, 87, 92, 93, 95, 96, 102, 108, 110, 111, 113, 116, 117, 122, 125, 128, 131, 132, 135, 137, 138, 143, 150, 152, 153, 155, 162 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Solutions of the equation (2*n+7)' = 1, where n' is the arithmetic derivative of n. [Paolo P. Lava, Nov 15 2012] LINKS Tony D. Noe and Jonathan Vos Post, Primes in Fibonacci n-step and Lucas n-step Sequences, J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4 EXAMPLE If n=0, then 2*0 + 7 = 7 (prime). If n=15, then 2*15 + 7 = 37 (prime). If n=27, then 2*27 + 7 = 61 (prime). MATHEMATICA (Prime[Range[4, 100]]-7)/2 [From Vladimir Joseph Stephan Orlovsky, Feb 08 2010] PROG (MAGMA)[n: n in [0..170]| IsPrime(2*n+7)][From V. Librandi, Dec 21 2010] CROSSREFS Cf. A153053 (Numbers n such that 2n+7 is not a prime) Numbers n such that 2n+k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), this seq(k=7), A155722 (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19). Numbers n such that 2n-k is prime: A006254 (k=1), A098090 (k=3), A089253 (k=5), A089192 (k=7), A097069 (k=9), A097338 (k=11), A097363 (k=13), A097480 (k=15), A098605 (k=17), A097932 (k=19). Sequence in context: A035057 A005099 A161720 * A050834 A179799 A191884 Adjacent sequences:  A105757 A105758 A105759 * A105761 A105762 A105763 KEYWORD easy,nonn AUTHOR Parthasarathy Nambi, May 04 2005 EXTENSIONS More terms from Rick L. Shepherd, May 18 2005 STATUS approved

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Last modified May 23 16:43 EDT 2013. Contains 225610 sequences.