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A085469 Decimal expansion of Madelung constant (negated) for simple cubic lattice. +0
4
1, 7, 4, 7, 5, 6, 4, 5, 9, 4, 6, 3, 3, 1, 8, 2, 1, 9, 0, 6, 3, 6, 2, 1, 2, 0, 3, 5, 5, 4, 4, 3, 9, 7, 4, 0, 3, 4, 8, 5, 1, 6, 1, 4, 3, 6, 6, 2, 4, 7, 4, 1, 7, 5, 8, 1, 5, 2, 8, 2, 5, 3, 5, 0, 7, 6, 5, 0, 4, 0, 6, 2, 3, 5, 3, 2, 7, 6, 1, 1, 7, 9, 8, 9, 0, 7, 5, 8, 3, 6, 2, 6, 9, 4, 6, 0, 7, 8, 8, 9, 9, 3 (list; cons; graph; listen)
OFFSET

1,2

COMMENT

This is the electrostatic potential at the origin produced by unit charges at all nonzero lattice points.

REFERENCES

Richard E. Crandall, Topics in Advanced Scientific Computation, Springer, Telos books, 1996. pages 73-79.

S. R. Finch, Mathematical Constants, Cambridge, 2003, p. 76

Andre Hautot, New applications of Poisson's summation formula, J of Phys, A vol. 8 #6, 1975 pp. 853-862.

Sadri Hassani, Mathematical Methods Using Mahematica: For Students of Physics and Related Fields, Springer, NY, page 60.

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1847

D. H. Bailey, J. M. Borwein, V. Kapoor and E. Weisstein, Ten Problems in Experimental Mathematics

R. E. Crandall and J. P. Buhler, Elementary function expansions for Madelung constants,J. Phys. A: Math. Gen. 20 (1987) no 16, 5497-5510

R. E. Crandall and J. P. Buhler, The potential within a crystal lattice,J. Phys. A: Math. Gen. 20 (1987) no 9, 2279-2292

E. R. Fuller Jr and E. R. Naimon, Electrostatic Contributions to the Brugger-Type Elastic Constants,Phys. Rev. B 6 (1971) no 10, 3609-3620

Simon Plouffe, Madelung constant

S. Plouffe, The Levy constant

Sandeep Tyagi, New series representation of the Madelung constant, Prog. Theor. Phys. 114 (2005) No 3, 517-521

Eric Weisstein's World of Mathematics, Benson's Formula

Eric Weisstein's World of Mathematics, Madelung Constants

FORMULA

Sum_{i, j, k not all 0} (-1)^(i+j+k)/sqrt(i^2+j^2+k^2).

EXAMPLE

-1.7475645946331821906362120355443974034851614366247417581528253507...

MATHEMATICA

RealDigits[ 12Pi*Sum[ Sech[Pi/2*Sqrt[(2j + 1)^2 + (2k + 1)^2]]^2, {j, 0, 40}, {k, 0, 40}], 10, 111][[1]] (from Robert G. Wilson v (rgwv(at)rgwv.com), Jul 12 2005)

PROGRAM

Contribution from Harry J. Smith (hjsmithh(AT)sbcglobal.net), May 15 2009: (Start)

(PARI) { default(realprecision, 1848); Madelung=-1.7475645946331821906362120355443974034851614366247417581\

5282535076504062353276117989075836269460788993083258153875371059328\

2029944183828013036933002156599363282376607172297568659238037167203\

8104106034214556064382777786832173132243697558773426250474787821285\

0860567916681675739924476841297036782518576281093713133720767071931\

9742497158115723096992309669273949657781107222671520547409011506891\

5716583082820050184892117803134673122964985828828184357133159143170\

0549563253348875363026704256274869484380028002592700268475574364975\

5049224613623992040015750630397214664811151237364010295066011939046\

7194373312530445102911514639759331918047977946099333746429426562908\

9693447792968854190440791425583272199718409067468023761538935445655\

0360273028544084934430280626704418241200439741867661772447563953444\

2306853849527943580751895490309305073843954464206438717926390780392\

0744282097957917736992304082214374645668043105692663197550459224432\

4807489408062474936107093630914922436898693314090379682324079004628\

4485812201497496519179081118204181820099174737652482957295684972796\

0238432587361742516304301213253823307779481444598420343673216212916\

2257903116101353527417534916776824438057139382407124829068734888254\

4125452570636795213611364128355999680725389089412120267587472631283\

4068262537606780890814341434286117388903537106985249308735988759660\

2363184706607516442145683455586623676605437844742512217481810852938\

2986359330038858941133489312302314299432802377837641811377123806642\

4808681158556451188180538368104068069306152452657895325624057864079\

5650016172016637963148270800941668173022273735813292616204948281860\

4313652035571121839219375759423906825690022886650812437760991098879\

3853419448765682333487553786009201932911164565934512096197118655146\

2827591256212354525900502281084479644187471007265894559896882147628\

71074726392395758480653025376082029590142679877534; x=-Madelung; for (n=1, 1847, d=floor(x); x=(x-d)*10; write("b085469.txt", n, " ", d)); } (End)

CROSSREFS

Cf. A005875.

Cf. A108778 = Continued fraction. [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), May 13 2009]

Sequence in context: A160575 A153586 A153186 this_sequence A050996 A085541 A133055

Adjacent sequences: A085466 A085467 A085468 this_sequence A085470 A085471 A085472

KEYWORD

nonn,cons

AUTHOR

Eric Weisstein (eric(AT)weisstein.com), Jul 01, 2003

EXTENSIONS

Entry revised by N. J. A. Sloane (njas(AT)research.att.com), Apr 12, 2004

Fixed my PARI program, had -n Harry J. Smith (hjsmithh(AT)sbcglobal.net), May 19 2009

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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