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A071690
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Number of ways to write n as n = x*y*z*t/(x+y+z+t) 1<=x<=y<=z<=t<=n.
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0
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1, 0, 1, 1, 2, 1, 3, 2, 6, 1, 8, 1, 7, 6, 9, 1, 15, 1, 10, 5, 8, 2, 21, 5, 10, 6, 15, 2, 28, 1, 16, 8, 11, 11, 27, 2, 9, 6, 30, 1, 35, 3, 18, 17, 9, 3, 43, 8, 30
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OFFSET
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1,5
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LINKS
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Table of n, a(n) for n=1..49.
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PROG
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(PARI) for(n=1, 50, print1(sum(a=1, n, sum(b=1, a, sum(c=1, b, sum(d=1, c, if(a*b*c*d/(a+b+c+d)-n, 0, 1))))), ", "))
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CROSSREFS
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Sequence in context: A014000 A075257 A073711 * A114653 A069481 A098911
Adjacent sequences: A071687 A071688 A071689 * A071691 A071692 A071693
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre, Jun 23 2002
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STATUS
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approved
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