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 A060239 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). 3
 1, -1, 4, -8, 128, 512, -18432, 73728, -884736, -14155776, 1415577600, 11324620800, -1630745395200, -58706834227200, -3757237390540800, 30057899124326400, -7694822175827558400, -92337866109930700800 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Enrique PĂ©rez Herrero, Table of n, a(n) for n = 1..100 FORMULA a(n) = A001088(n)*A060238(n)/n!. PROG (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 CROSSREFS Cf. A001088, A060238. Sequence in context: A182967 A013049 A193155 * A127943 A012498 A180745 Adjacent sequences:  A060236 A060237 A060238 * A060240 A060241 A060242 KEYWORD sign AUTHOR MCKAY john (mckay(AT)cs.concordia.ca), Mar 21 2001 STATUS approved

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Last modified April 10 11:15 EDT 2021. Contains 342845 sequences. (Running on oeis4.)