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 A144425 Nonprimes of the form (p(n)-2*(n-1))/7, where p(n)=n-th prime. 0
 1, 33, 35, 39, 49, 77, 77, 105, 117, 119, 133, 145, 145, 155, 159, 185, 201, 205, 213, 213, 215, 225, 225, 235, 237, 243, 249, 255, 273, 295, 299, 301, 319, 319, 321, 327, 329, 341, 345, 345, 365, 375, 377, 381, 399, 405, 405, 413, 485, 485, 493, 493, 497 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..53. EXAMPLE If n=9, then (p(9)-2*(9-1))/7=(23-16)/7=1=a(1). If n=75, then (p(75)-2*(75-1))/7=(379-148)/7=33=a(2). If n=79, then (p(79)-2*(79-1))/7=(401-156)/7=35=a(3). If n=86, then (p(86)-2*(86-1))/7=(443-170)/7=39=a(4). If n=90, then (p(90)-2*(90-1))/7=(463-178)/7=49=a(5). If n=143, then (p(143)-2*(143-1))/7=(823-284)/7=77=a(6), etc. MATHEMATICA Select[(Last[#]-2(First[#]-1))/7&/@Table[{n, Prime[n]}, {n, 800}], IntegerQ[#] && !PrimeQ[#]&] (* Harvey P. Dale, Sep 14 2011 *) CROSSREFS Cf. A000040, A141468. Sequence in context: A344139 A140143 A041543 * A180329 A367782 A356765 Adjacent sequences: A144422 A144423 A144424 * A144426 A144427 A144428 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Oct 08 2008 EXTENSIONS More terms from R. J. Mathar, Apr 13 2010 STATUS approved

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Last modified June 24 00:02 EDT 2024. Contains 373661 sequences. (Running on oeis4.)