Re: Processing lists of unrelated numbers with Do or While statement

*To*: mathgroup at smc.vnet.net*Subject*: [mg39185] Re: [mg39175] Processing lists of unrelated numbers with Do or While statement*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Mon, 3 Feb 2003 01:08:25 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I don't quite understand what you mean by "processing unrelated numbers", but ... first of all , you can just map your test function onto range of integers, e.g. And @@ (PrimePi[2#] - PrimePi[#] ¡Ã 1 & /@ Prime/@Range[2,100]) True Of course if you want to know the actual difference you can use: In[17]:= PrimePi[2#]-PrimePi[#]&/@Prime/@Range[2,100] Out[17]= {1,1,2,3,3,4,4,5,6,7,9,9,9,9,11,13,12,13,14,13,15,15,16,19,20,19,19,18,1 8,23,\ 23,25,25,27,26,28,28,28,28,30,30,32,32,32,32,35,38,38,38,39,39,39,41,42, 43,42,\ 42,42,42,42,44,49,50,49,49,54,54,56,55,55,55,57,58,59,59,60,60,60,61,64, 64,66,\ 66,66,67,67,68,68,67,67,70,71,71,73,72,73,77,76,80} and of course lots of different variants of this. Andrzej Kozlowski Yokohama, Japan http://www.mimuw.edu.pl/~akoz/ http://platon.c.u-tokyo.ac.jp/andrzej/ On Sunday, February 2, 2003, at 03:13 PM, Diana wrote: > Folks, > > I had a problem recently where I tried to determing the PrimePi value > of 2 > times a number minus that number. This is verifying the Bertrand's > Postulate: > > PrimePi(2x) - PrimePi(x) >=1 for all x >=2, elements of Z. > > Well, > > I finally came up with: > PrimePi[2*{2, 3, 5, 7, 13, 23, 43, 83, 163, 317, 631, 1259, 2503, > 4001} - > {2, 3, 5, 7, > 13, 23, 43, 83, 163, 317, 631, 1259, 2503, 4001}] > > gives: > {1, 2, 3, 4, 6, 9, 14, 23, 38, 66, 115, 205, 368, 551} > the desired answer. > Is there a way to process unrelated numbers with a Do or While or > NestWhile > statement? > Thanks, > Diana > > -- > ===================================================== > "God made the integers, all else is the work of man." > L. Kronecker, Jahresber. DMV 2, S. 19. > > > >