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A060239
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a(n) = determinant(P*Q)/n! where P, Q are n X n matrices with P[i,j]=lcm(i,j), Q[i,j]=gcd(i,j).
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3
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1, -1, 4, -8, 128, 512, -18432, 73728, -884736, -14155776, 1415577600, 11324620800, -1630745395200, -58706834227200, -3757237390540800, 30057899124326400, -7694822175827558400, -92337866109930700800
(list;
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listen;
history;
text;
internal format)
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OFFSET
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1,3
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LINKS
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Enrique Pérez Herrero, Table of n, a(n) for n = 1..100
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FORMULA
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a(n) = A001088(n)*A060238(n)/n!.
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PROG
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(Sage)
def A060239(n):
P = Matrix(lambda i, j: lcm(i+1, j+1), nrows=n)
Q = Matrix(lambda i, j: gcd(i+1, j+1), nrows=n)
return (P*Q).det()/factorial(n) # D. S. McNeil, Jan 16 2011
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CROSSREFS
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Cf. A001088, A060238.
Sequence in context: A182967 A013049 A193155 * A127943 A012498 A180745
Adjacent sequences: A060236 A060237 A060238 * A060240 A060241 A060242
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KEYWORD
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sign
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AUTHOR
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MCKAY john (mckay(AT)cs.concordia.ca), Mar 21 2001
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STATUS
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approved
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