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Search: id:A085015
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| A085015 |
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Multiplicity of the root 1 in the characteristic polynomial mod 2 of the n X n matrix with entries binomial(i+j,i), 0<=i,j<n. |
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+0
2
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| 0, 1, 0, 3, 2, 5, 0, 3, 2, 5, 0, 11, 6, 9, 4, 7, 6, 9, 4, 15, 10, 21, 0, 11, 6, 9, 4, 15, 10, 13, 8, 11, 10, 13, 8, 19, 14, 25, 4, 15, 10, 21, 0, 43, 22, 33, 12, 23, 18, 21, 16, 27, 22, 33, 12, 23, 18, 21, 16, 27, 22, 25, 20, 23, 22, 25, 20, 31, 26, 37, 16, 27, 22, 33, 12, 55, 34, 45
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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R. Bacher and R. Chapman, Symmetric Pascal matrices modulo p, European J. Combin. 25 (2004), no. 4, 459-473.
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FORMULA
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a(0)=0 and a(2^l-k)=(2^l+2*(-1)^l)/3-k+2*a(k) for 0<=k<=2^(l-1).
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MAPLE
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f := (l, n)->if 2^l<(n) then f(l+1, n); else l fi; fo := n->f(0, n); a := n->if n=0 then 0 else (2^fo(n)+2*(-1)^fo(n))/3-(2^fo(n)-n)+2*a(2^fo(n)-n); fi;
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CROSSREFS
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Sequence in context: A019116 A082493 A021887 this_sequence A083254 A068453 A111986
Adjacent sequences: A085012 A085013 A085014 this_sequence A085016 A085017 A085018
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KEYWORD
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easy,nonn
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AUTHOR
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Roland Bacher (roland.bacher(AT)ujf-grenoble.fr), Jun 18 2003
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