検索: seq:1,2,5,16,68
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1, 1, 2, 5, 16, 68, 399, 3348, 41417, 775234, 22445788, 1024347395, 74876701760, 8888457145166, 1734062627778860
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OFFSET
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0,3
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LINKS
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Table of n, a(n) for n=0..14.
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FORMULA
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a(n) = A107946(2^n).
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PROG
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(PARI) {a(n)=local(A=[1, 1], B=[1]); for(i=1, n-1, B=concat(B, vector(#B, k, polcoeff(Ser(A)/(1-x), #B+k-1))); A=concat(A, B); ); A[2^(n-1)]}
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CROSSREFS
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Cf. A107946, A107947.
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna, May 28 2005
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STATUS
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approved
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A058673
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Number of matroids on n labeled points.
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+30
3
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OFFSET
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0,2
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LINKS
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Table of n, a(n) for n=0..8.
W. M. B. Dukes, Tables of matroids.
W. M. B. Dukes, Counting and Probability in Matroid Theory, Ph.D. Thesis, Trinity College, Dublin, 2000.
W. M. B. Dukes, The number of matroids on a finite set, arXiv:math/0411557 [math.CO], 2004.
W. M. B. Dukes, On the number of matroids on a finite set, Séminaire Lotharingien de Combinatoire 51 (2004), Article B51g.
Index entries for sequences related to matroids
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CROSSREFS
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Row sums of A058669. Closely related to A114491.
Cf. A055545.
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KEYWORD
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nonn,nice,more
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AUTHOR
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N. J. A. Sloane, Dec 30 2000
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STATUS
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approved
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A220840
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Number of 1-cop-win graphs of order n.
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+30
0
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OFFSET
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1,3
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LINKS
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Table of n, a(n) for n=1..10.
W. D. Baird, Cops and robbers on graphs and hypergraphs, MS Thesis, Applied Mathematics, Ryerson University, 2011. - From N. J. A. Sloane, Dec 29 2012
W. Baird, A. Beveridge, A. Bonato et al., On the minimum order of k-cop-win graphs, 2012.
W. Baird, A. Beveridge, A. Bonato, P. Codenotti, A. Maurer et al., On the minimum order of k-cop-win graphs, Ryerson Applied Mathematics Laboratory. Technical Report, Ryerson University, 2014.
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KEYWORD
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nonn,more
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AUTHOR
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N. J. A. Sloane, Dec 23 2012
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STATUS
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approved
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