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A160457
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a(n) = n^2 - 2*n + 2.
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2
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2, 1, 2, 5, 10, 17, 26, 37, 50, 65, 82, 101, 122, 145, 170, 197, 226, 257, 290, 325, 362, 401, 442, 485, 530, 577, 626, 677, 730, 785, 842, 901, 962, 1025, 1090, 1157, 1226, 1297, 1370, 1445, 1522, 1601, 1682, 1765, 1850, 1937, 2026, 2117, 2210, 2305, 2402, 2501, 2602, 2705, 2810
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OFFSET
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0,1
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COMMENTS
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Competition number of the complete bipartite graph K_n,n.
Formula given on p. 3 of Sano.
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LINKS
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Table of n, a(n) for n=0..54.
Yoshio Sano, The competition numbers of regular polyhedra, arXiv:0905.1763 [math.CO], 2009.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
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a(n) = a(n-1)+2*n-3 (with a(0)=2). - Vincenzo Librandi, Dec 03 2010
a(n)= +3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: -(2-5*x+5*x^2)/(x-1)^3.
a(n) = A002522(n-1). - Michel Marcus, Feb 03 2016
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MATHEMATICA
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Table[n^2-2*n+2, {n, 0, 5!}] (* Vladimir Joseph Stephan Orlovsky, Dec 29 2010 *)
LinearRecurrence[{3, -3, 1}, {2, 1, 2}, 60] (* Harvey P. Dale, Mar 29 2015 *)
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PROG
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(PARI) vector(100, n, n--; n^2 - 2*n + 2)
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CROSSREFS
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Cf. A002522, A160450.
Sequence in context: A117715 A330962 A327194 * A107087 A279955 A280339
Adjacent sequences: A160454 A160455 A160456 * A160458 A160459 A160460
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post, May 14 2009
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EXTENSIONS
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More terms from Vincenzo Librandi, Nov 08 2009
Sequence corrected by Joerg Arndt, Dec 03 2010
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STATUS
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approved
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