November 2005 - mathfun@mailman.xmission.com

[math-fun] Query
by David Wilson 30 Nov '05

30 Nov '05

Are there any math-funners or seqfans working at amazon.com? -------------------------------- - David Wilson

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[math-fun] Re: ellipse packing
by Dean Hickerson 30 Nov '05

30 Nov '05

Richard Schroeppel asked: > Puzzle: Choose some specific ellipse, say a=2 b=1. > Find any packing that has a higher packing density > than circles in the plane (the simple hex packing). A related question: Suppose we're allowed to use more than one shape of ellipse, as long as all of them have the same area. Can we get a higher density than the hex packing of circles? Dean Hickerson dean(a)math.ucdavis.edu

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[math-fun] Clyde Haberman: "A Bit Less Than the Sum of Its Parts" - - - plus Google's violation of privacy
by dasimov＠earthlink.net 30 Nov '05

30 Nov '05

An opinion piece by Clyde Haberman, "A Bit Less Than the Sum of Its Parts", appeared in the NY Times, I think today. The subhead for the article makes it seem to be about math education. Since I don't have access to their "Total Access" package (a mere $50/year) and didn't buy the paper, I don't know what it says. Can someone who read the article post at least a brief summary of what it says? ------------------------------------------------------------------ In other news, the NY Times printed an editorial detailing some of Google's violations of personal privacy here: http://www.nytimes.com/2005/11/28/opinion/28mon4.html?n=Top%2fOpinion%2fEdi…. I was so dismayed that I immediately wrote Google, asking them to delete all information they may have about me, and to in fact sever all ties (E.g., I had been registered for Google Groups.) I fully expect them to totally ignore me. But I'm interested in what others think about this editorial. --Dan

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[math-fun] Epsilon forms
by Thane Plambeck 29 Nov '05

29 Nov '05

They say this won't make landfall, so I guess for every epsilon there might not be a delta http://www.cbsnews.com/stories/2005/11/29/tech/main1084017.shtml -- Thane Plambeck http://www.plambeck.org/ehome.htm

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Re: [math-fun] ellipse packing
by N. J. A. Sloane 29 Nov '05

29 Nov '05

For the 3-D version, where the density of the fcc can be beaten using ellipsoids, see A. Donev, I. Cisse, D. Sachs, E. A. Variano, F. H. Stillinger, R. Connelly, S. Torquato, and P. M. Chaikin, Improving the Density of Jammed Disordered Packings using Ellipsoids, Science, 303, 990-993 (2004). A. Donev, F. H. Stillinger, P. M. Chaikin, and S. Torquato, Unusually Dense Crystal Ellipsoid Packings, Physical Review Letters, 92, 255506 (2004). Neil

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[math-fun] test message - ignore it
by Schroeppel, Richard 29 Nov '05

29 Nov '05

This is a test message. Please ignore it. Rich

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[math-fun] ellipse packing
by Schroeppel, Richard 29 Nov '05

29 Nov '05

Puzzle: Choose some specific ellipse, say a=2 b=1. Find any packing that has a higher packing density than circles in the plane (the simple hex packing). I can beat the density of simple square packing of circles, by puting two 1x2 ellipses in a square, alternating horz and vertical in a checkerboard tiling, and then stretching the ellipses a smidgen. But this probably is still less than the circle-hex density. Rich

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RE: [math-fun] Huge Alphametic
by Eric Angelini 29 Nov '05

29 Nov '05

Waow, Don, how quick ! I'll write something about this alphametic french record on my website and will quote your discovery asap. Thanks thousand times ! Best, É. -----Message d'origine----- De : math-fun-bounces+eric.angelini=kntv.be(a)mailman.xmission.com De la part de Don Reble Envoyé : lundi 28 novembre 2005 23:31 À : math-fun Objet : Re: [math-fun] Huge Alphametic > 11011011*TROIS + k*ZERO = TRENTETROISMILLIONSTRENTETROISMILLETRENTETROIS > > What could be the highest value of « k » to make > this equation doubly true ? k = 9052154594080843506502230384781217375224160 E I L M N O R S T Z 0 4 6 5 3 2 7 8 9 1 -- Don Reble djr(a)nk.ca -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. _______________________________________________ math-fun mailing list math-fun(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun

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[math-fun] Huge Alphametic
by Eric Angelini 28 Nov '05

28 Nov '05

Hello math-fun, I need a little help with a huge calculation. It's about cryptarithms (or alphametics) I'm trying to find *the* ultimate, biggest ever cryptarithm in french (solution must be unique and *big* is evaluated in term of « largest quantity of terms left to the equal sign ») I think that this ultimate cryptarithm will look like that : TROIS + TROIS + TROIS + ... + TROIS + ZERO + ZERO + ZERO + ... + ZERO = TRENTETROISMILLIONSTRENTETROISMILLETRENTETROIS Ten letters are used. This could be re-written in a more compact form for easier use : 11011011*TROIS + k*ZERO = TRENTETROISMILLIONSTRENTETROISMILLETRENTETROIS What could be the highest value of « k » to make this equation doubly true ? If, after having chosen an arbitrarly 42-digit long value for k, I drop the according equation into Robert B. Israel's (marvelous) applet, I'm in trouble ! http://www.geocities.com/rbisrael/metic/metic.html To see what I mean, copy and paste this into the applet : 991*UN + NEUF + 51*ZERO = MILLE (k=51, here) Best, É.

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Re: [math-fun] Abramowitz & Stegun
by Mike Stay 28 Nov '05

28 Nov '05

On 11/28/05, Thomas Baruchel <tbaruchel(a)free.fr> wrote: > On Dim, nov 27, 2005 at 01:08:25 -0700, Schroeppel, Richard wrote: > > Simon Plouffe has a scanned copy of A&S online at > > > > http://www.lacim.uqam.ca/~plouffe/articles/Abramowitz&Stegun.pdf > > And I once found a DJVU version online (much smaller file than PDF > and much quicker navigation with djview than with xpdf). > > If I have the right to do it, I can put it somewhere, but would it > be legal ? Yes. The whole thing is public domain, since it's a government publication. > -- > Thomas Baruchel > Home Page: http://baruchel.free.fr/~thomas/ > > _______________________________________________ > math-fun mailing list > math-fun(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun > -- Mike Stay metaweta(a)gmail.com http://math.ucr.edu/~mike

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