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A059383
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Product J_4(i), i=1..n.
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7
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1, 15, 1200, 288000, 179712000, 215654400000, 517570560000000, 1987470950400000000, 12878811758592000000000, 120545678060421120000000000, 1764788726804565196800000000000, 33883943554647651778560000000000000, 967725427920736934795673600000000000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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a(n) is also the determinant of the symmetric n X n matrix M defined by M(i,j) = gcd(i,j)^4 for 1 <= i,j <= n. - Avi Peretz (njk(AT)netvision.net.il), Mar 22 2001
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REFERENCES
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L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 203, #17.
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LINKS
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MATHEMATICA
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JordanTotient[n_, k_:1]:=DivisorSum[n, #^k*MoebiusMu[n/#]&]/; (n>0)&&IntegerQ[n]; A059383[n_]:=Times@@(JordanTotient[#, 4]&/@Range[n]); (* Enrique Pérez Herrero, Aug 12 2011 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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