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A227107
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Numerators of harmonic mean H(n,4), n >= 0.
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2
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0, 8, 8, 24, 4, 40, 24, 56, 16, 72, 40, 88, 6, 104, 56, 120, 32, 136, 72, 152, 20, 168, 88, 184, 48, 200, 104, 216, 7, 232, 120, 248, 64, 264, 136, 280, 36, 296, 152, 312, 80, 328, 168, 344, 22, 360, 184, 376, 96, 392, 200, 408, 52, 424, 216
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OFFSET
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0,2
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COMMENTS
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a(n) = numerator(H(n,4)) = numerator(8*n/(n+4)), n>=0, with H(n,4) the harmonic mean of n and 4.
The corresponding denominators are given in A000265(n+4), n >= 0.
a(n+4), n>=0, is the fourth column (m=4) of the triangle A227041.
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LINKS
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FORMULA
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a(n) = numerator(8*n/(n+4)), n >= 0.
a(n) = 8*n/gcd(n+4,8*n) = 8*n/gcd(n+4,32), n >= 0.
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EXAMPLE
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The rationals H(n,4) begin: 0, 8/5, 8/3, 24/7, 4, 40/9, 24/5, 56/11, 16/3, 72/13, 40/7, 88/15, 6, 104/17, 56/9, 120/19, ...
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CROSSREFS
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KEYWORD
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nonn,frac,easy
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AUTHOR
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STATUS
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approved
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