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Search: id:A055137
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| A055137 |
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Regard triangle of rencontres numbers (see A008290) as infinite matrix, compute inverse, read by rows. |
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+0 3
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| 1, 0, 1, -1, 0, 1, 2, -3, 0, 1, -3, 8, -6, 0, 1, 4, -15, 20, -10, 0, 1, -5, 24, -45, 40, -15, 0, 1, 6, -35, 84, -105, 70, -21, 0, 1, -7, 48, -140, 224, -210, 112, -28, 0, 1, 8, -63, 216, -420, 504, -378, 168, -36, 0, 1, -9, 80, -315, 720, -1050, 1008, -630, 240, -45, 0, 1
(list; table; graph; listen)
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OFFSET
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0,7
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COMMENT
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The n-th row consists of coefficients of the characteristic polynomial of the adjacency matrix of the complete n-graph.
Triangle of coefficients of det(M(n)) where M(n) is the n X n matrix m(i,j)=x if i=j, m(i,j)=i/j otherwise. - Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 01 2003
T is an example of the group of matrices outlined in the table in A132382--the associated matrix for rB(0,1). The e.g.f. for the row polynomials is exp(x*t) * exp(x) *(1-x). T(n,k) = Binomial(n,k)* s(n-k) where s = (1,0,-1,-2,-3,...) with an e.g.f. of exp(x)*(1-x) which is the reciprocal of the e.g.f. of A000166. [From Tom Copeland (tcjpn(AT)msn.com), Sep 10 2008]
Contribution from Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Feb 20 2009: (Start) Row sums are: {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,...}. (End)
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REFERENCES
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Norman Biggs, Algebraic Graph Theory, 2nd ed. Cambridge University Press, 1993. p. 17.
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p.184 problem 3. [From Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Feb 20 2009]
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FORMULA
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G.f.: (x-n+1)*(x+1)^(n-1) = sum T(n, k)x^k. T(n, k) = (1-n+k)*C(n, k).
k-th column has o.g.f. x^k(1-(k+2)x)/(1-x)^(k+2). k-th row gives coefficients of (x-k)(x+1)^k. - Paul Barry (pbarry(AT)wit.ie), Jan 25 2004
t(n,m)=Coefficiemtslist[Det[Table[If[i == j, x, 1], {i, 1, n}, {j, 1, n}],x] [From Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Feb 20 2009]
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EXAMPLE
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1; 0,1; -1,0,1; -2,-3,0,1; -3,-8,-6,0,1; ...
Contribution from Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Feb 20 2009: (Start)
{1},
{0, 1},
{-1, 0, 1},
{2, -3, 0, 1},
{-3, 8, -6, 0, 1},
{4, -15, 20, -10, 0, 1},
{-5, 24, -45, 40, -15, 0, 1},
{6, -35, 84, -105, 70, -21, 0, 1},
{-7, 48, -140, 224, -210, 112, -28, 0, 1},
{8, -63, 216, -420, 504, -378, 168, -36, 0, 1},
{-9, 80, -315, 720, -1050, 1008, -630, 240, -45, 0, 1} (End)
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MATHEMATICA
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Contribution from Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Feb 20 2009: (Start)
Clear[M, a, n, m, i, j];
M[n_] := Table[If[i == j, x, 1], {i, 1, n}, {j, 1, n}];
a = Join[{{1}}, Table[CoefficientList[Det[M[n]], x], {n, 1, 10}]];
Flatten[%] (End)
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PROGRAM
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(PARI) T(n, k)=(1-n+k)*if(k<0|k>n, 0, n!/k!/(n-k)!)
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CROSSREFS
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Absolute values of columns 1, 2: A005563, A005564.
Sequence in context: A112168 A072516 A106450 this_sequence A143325 A128888 A163575
Adjacent sequences: A055134 A055135 A055136 this_sequence A055138 A055139 A055140
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KEYWORD
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sign,tabl
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Apr 25 2000
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EXTENSIONS
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Additional comments from Michael Somos, Jul 04 2002
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