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 A154296 Primes of the form (1+2+3+...+m)/15 = A000217(m)/15, for some m. 9
 3, 7, 29, 31 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Original definition : Primes of the form 1/x+2/x+3/x+4/x+5/x+6/x+7/x+..., x=15. The corresponding m-values are m=9, 14, 29, 30. It is clear that for m>30, T(m)/15 = m(m+1)/30 cannot be a prime. - M. F. Hasler, Dec 31 2012 All of the sequences A154296, ..., A154304 could or should be grouped together in a single ("fuzzy"?) table. It would be more interesting to have the function f(n) which gives the *number* of primes of the form T(k)/n. - M. F. Hasler, Jan 06 2013 LINKS MATHEMATICA lst={}; s=0; Do[s+=n/15; If[Floor[s]==s, If[PrimeQ[s], AppendTo[lst, s]]], {n, 0, 9!}]; lst Select[(Accumulate[Range[200]])/15, PrimeQ] (* Harvey P. Dale, Oct 30 2011 *) PROG (PARI) select(x->denominator(x)==1 & isprime(x), vector(30, m, m^2+m)/30)  \\ - M. F. Hasler, Dec 31 2012 CROSSREFS Cf. A057570, A154293, A154297, A154298, A154299, A154300, A154301, A154302, A154303, A154304. Sequence in context: A018989 A325258 A073126 * A038900 A068485 A019352 Adjacent sequences:  A154293 A154294 A154295 * A154297 A154298 A154299 KEYWORD nonn,fini,full,easy AUTHOR Vladimir Joseph Stephan Orlovsky, Jan 06 2009 EXTENSIONS Edited by M. F. Hasler, Dec 31 2012 STATUS approved

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Last modified October 19 03:54 EDT 2019. Contains 328211 sequences. (Running on oeis4.)