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The Triangle's Bottom (Posted on 2008-02-05) Difficulty: 2 of 5
Let T be the set of triangular numbers and T* be the set of all products of any two triangular numbers. Show that:

1. Among elements of T, each of the digits 0,1,5 and 6 occur in the units place twice as frequently as each of the digits 3 and 8. (More precisely, if MBk is the set of elements of T that are less than B and end in k, then, e.g., MB1/MB8 approaches 2 as B approaches infinity.)

2. None of the elements of T* end in 2 or 7.

See The Solution Submitted by FrankM    
Rating: 3.0000 (1 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Some ThoughtsDid it in your sleep..FrankM2008-02-06 08:36:11
SolutionSolutionDej Mar2008-02-06 02:11:50
SolutionSolutionPraneeth2008-02-05 22:53:46
SolutionsolutionCharlie2008-02-05 14:48:22
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