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Search: id:A071547
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| A071547 |
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Determinant of the n X n matrix whose element (i,j) equals f(|i-j|) where f(n) is the sum of middle divisors (A071090). |
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+0
1
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| 0, -1, 2, 0, -2, 3, 8, -259, -9006, 37575, 1988916, 41615129, -444915500, 4752358604, -50506657344, 532544416084, -4450492081868, -10234691885873, 241215169689690, 21696729746925312, 123619114295636184, 174381272189413488, -43909101832286346168, -439142701170244441024
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OFFSET
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1,3
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MATHEMATICA
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f[n_] := If[n > 0, Plus @@ Select[Divisors[n], Sqrt[n/2] <= # < Sqrt[n*2] &], 0]; Table[ Det[ Table[ f[ Abs[i - j]], {i, 1, n}, {j, 1, n}]], {n, 1, 25}]
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CROSSREFS
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Cf. A071090.
Sequence in context: A028376 A059235 A072514 this_sequence A089839 A151668 A086151
Adjacent sequences: A071544 A071545 A071546 this_sequence A071548 A071549 A071550
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KEYWORD
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sign
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), May 30 2002
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