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Search: id:A000127
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| A000127 |
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Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes. (Formerly M1119 N0427)
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+0 19
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| 1, 2, 4, 8, 16, 31, 57, 99, 163, 256, 386, 562, 794, 1093, 1471, 1941, 2517, 3214, 4048, 5036, 6196, 7547, 9109, 10903, 12951, 15276, 17902, 20854, 24158, 27841, 31931, 36457, 41449, 46938, 52956, 59536, 66712, 74519, 82993, 92171, 102091
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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R. B. Banks, Slicing Pizzas, Racing Turtles, and Further Adventues in Applied Mathematics, Princeton Univ. Press, 1999. See p. 28.
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 72, Problem 2.
J. H. Conway and R. K. Guy, The Book of Numbers, Copernicus Press, NY, 1996, Chap. 3.
J.-M. De Koninck & A. Mercier, 1001 Problemes en Theorie Classique Des Nombres, Problem 33 pp. 18; 128 Ellipses Paris 2004.
A. Deledicq and D. Missenard, A La Recherche des Regions Perdues, Math. & Malices, No. 22 Summer 1995 issue pp. 22-3 ACL-Editions Paris.
M. Gardner, Mathematical Circus, pp. 177; 180-1 Alfred A. Knopf NY 1979
M. Gardner, The Colossal Book of Mathematics, 2001, p. 561.
James Gleick, Faster, Vintage Books, NY, 2000 (see pp. 259-261).
M. de Guzman, Aventures Mathematiques, Prob. B pp. 115-120 PPUR Lausanne 1990
Ross Honsberger; Mathematical Gems I, Chap. 9.
Ross Honsberger; Mathematical Morsels, Chap. 3.
Jeux Mathematiques et Logiques, Vol. 3 pp. 12; 51 Prob. 14 FFJM-SERMAP Paris 1988
J. N. Kapur, Reflections of a Mathematician, Chap.36, pp. 337-343, Arya Book Depot, New Delhi 1996.
D. A. Lind, On a class of nonlinear binomial sums, Fib. Quart., 3 (1965), 292-298.
I. Niven, Mathematics of Choice, pp. 158; 195 Prob. 40 NML 15 MAA 1965
M. Noy, "A Short Solution of a Problem in Combinatorial Geometry", Mathematics Magazine, pp. 52-3 69(1) 1996 MAA
C. S. Ogilvy, Tomorrow's Math, pp. 144-6 OUP 1972
D. J. Price, Some unusual series occurring in n-dimensional geometry, Math. Gaz., 30 (1946), 149-150.
A. M. Robert, A Course in p-adic Analysis, Springer-Verlag, 2000; p. 213.
Alfred S. Posamentier & Ingmar Lehmann, The (Fabulous) Fibonacci Numbers, Prometheus Books, NY, 2007, page 81-87.
C. D. Miller, V. E. Heeren, J. Hornsby, M. L. Morrow and J. Van Newenhizen, Mathematical Ideas, Tenth Edition, Pearson, Addison-Wesley, Boston, 2003, Cptr 1, 'The Art of Problem Solving, page 6.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
Math Forum, Regions of a circle Cut by Chords to n points.
S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures}, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
K. Uhland, A Blase of Glory
K. Uhland, Moser's Problem
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Eric Weisstein's World of Mathematics, Strong Law of Small Numbers
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FORMULA
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C(n-1, 4)+C(n-1, 3)+ ... +C(n-1, 0) = C(n, 4)+C(n, 2)+1 = C(n, 4)+C(n-1, 2)+n.
a(n) = Sum_{0 <= k <= 2} C(n, 2k) - Joel Sanderi (sanderi(AT)itstud.chalmers.se), Sep 08 2004
(n^4-6n^3+23n^2-18n+24)/24.
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MAPLE
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A000127 := n->1/24*n^4-1/4*n^3+23/24*n^2-3/4*n+1;
A000127 := n->(n^4 - 6*n^3 + 23*n^2 - 18*n + 24)/24;
A000127:=-(1-3*z+4*z**2-2*z**3+z**4)/(z-1)**5; [S. Plouffe in his 1992 dissertation.]
with (combstruct):ZL:=[S, {S=Sequence(U, card<r), U=Set(Z, card>=1)}, unlabeled]: seq(count(subs(r=6, ZL), size=m), m=0..41); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 08 2008
seq(sum(binomial(n, m), m=1..4)+1, n=0..41); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 17 2008
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MATHEMATICA
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f[n_] := Sum[Binomial[n, i], {i, 0, 4}]; Table[f@n, {n, 0, 40}] (* Robert G. Wilson v (rgwv@rgwv.com), Jun 29 2007 *)
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CROSSREFS
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Sequence in context: A054016 A051039 A056183 this_sequence A133552 A000128 A106399
Adjacent sequences: A000124 A000125 A000126 this_sequence A000128 A000129 A000130
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas
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EXTENSIONS
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Formula corrected and additional references from TORSTEN.SILLKE(AT)LHSYSTEMS.COM.
Additional correction from Jonas Paulson (jonasso(AT)sdf.lonestar.org), Oct 30 2003
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