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Search: id:A117109
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| A117109 |
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Moebius transform of {n+3 choose 4}. |
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+0
1
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| 1, 4, 14, 30, 69, 107, 209, 295, 480, 641, 1000, 1209, 1819, 2166, 2976, 3546, 4844, 5379, 7314, 8110, 10402, 11645, 14949, 15890, 20405, 21927, 26910, 29055, 35959, 37108, 46375, 48484, 57890, 61196, 73536, 75027, 91389, 93951, 110096, 114260
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Partial sums of a(n) give A015650(n)
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FORMULA
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a(n)=|{(x,y,z,w) : 1<=x<=y<=z<=w<=n, gcd(x,y,z,w,n)=1}|
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EXAMPLE
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a(2)=4 because of the quadruples (1,1,1,1), (1,1,1,2), (1,1,2,2), (1,2,2,2)
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CROSSREFS
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Sequence in context: A103779 A049451 A079776 this_sequence A140063 A051409 A072475
Adjacent sequences: A117106 A117107 A117108 this_sequence A117110 A117111 A117112
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KEYWORD
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nonn
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AUTHOR
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Steve Butler (sbutler(AT)math.ucsd.edu), Apr 18 2006
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