On Primitive 3-smooth Partitions of n

نویسنده

  • Michael Avidon
چکیده

A primitive 3-smooth partition of n is a representation of n as the sum of numbers of the form 2a3b, where no summand divides another. Partial results are obtained in the problem of determining the maximal and average order of the number of such representations. Results are also obtained regarding the size of the terms in such a representation, resolving questions of Erdős and Selfridge. 0. Introduction Recently Erdős proposed the following problem: let r(n) be the number of representations of n as the sum of 3-smooth numbers (integers of the form 23 with a, b ≥ 0), which are primitive (no summand divides another). Determine i. the maximal order of r(n), ii. the average order of r(n). It is easy to show that r(n) ≥ 1 for all n (see[1],[2]). In this paper partial results are obtained for both of these problems. Specifically, we prove: Theorem 1. For n ≥ 5, r(n) ≤ 1 2 · n, where α = log 2/ log 3 (≈ 0.631). Theorem 2. Let R(x) = ∑ n≤x r(n). Then x (log x)β+3/2 ¿ R(x)¿ x (log x)3/2 where β = 1 log 3 · log( log 6 log 2 ) + 1 log 2 · log( log 6 log 3 ) (≈ 1.570). Define g(n) as the maximum, over all representations, of the minimum term (e.g. 11=8+3=9+2, so g(11) = 3). Erdős has asked if limn→∞ g(n) = ∞. We answer this in the affirmative by proving: 1991 Mathematics Subject Classification. Primary 11P85, Secondary 05A17.

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عنوان ژورنال:
  • Electr. J. Comb.

دوره 4  شماره 

صفحات  -

تاریخ انتشار 1997