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A077122
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Let M_n be the n X n matrix M_(i,j) = 2^i-2^j then the characteristic polynomial of M_n = x^n-a(n)*x^(n-2).
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1
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0, 4, 56, 460, 2976, 16884, 88392, 438940, 2101232, 9794884, 44755608, 201359340, 894850368, 3937184404, 17180131304, 74446624060, 320691939984, 1374391631844, 5864066209080, 24922271951500, 105553133043680, 445668746679604, 1876499911846536
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 1/3 * [(n-2)4^(n+2) + 3*2^(n+4) - 4(n-4)]. - Ralf Stephan, May 09 2004
G.f.: 4*x*(1 + 2*x) / ((1 - x)^2*(1 - 2*x)*(1 - 4*x)^2).
a(n) = 12*a(n-1) - 53*a(n-2) + 106*a(n-3) - 96*a(n-4) + 32*a(n-5) for n>4.
(End)
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PROG
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(PARI) a(n)=polcoeff(charpoly(matrix(n, n, i, j, 2^i-2^j)), n-2)
(PARI) concat(0, Vec(4*x*(1 + 2*x) / ((1 - x)^2*(1 - 2*x)*(1 - 4*x)^2) + O(x^30))) \\ Colin Barker, Aug 30 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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