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A175455
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a(n) = H(n) * (lcm(1,2,...,n))^2, where H(n) = harmonic numbers (1/1 + 1/2 + ... + 1/n).
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1
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1, 6, 66, 300, 8220, 8820, 457380, 1917720, 17965080, 18600120, 2320468920, 2384502120, 412970037480, 422245703880, 430902992520, 1756076802480, 516336630329520, 524676485052720, 192260441419366320, 194970060218934000, 197550649551855600, 200013939369644400
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (1/1 + 1/2 + ... + 1/n) * (lcm(1,2,...,n))^2.
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EXAMPLE
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For n = 3, a(3) = (1/1 + 1/2 + 1/3) * (1*2*3)^2 = (11/6) * 36 = 66.
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PROG
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(PARI) a(n)={sum(k=1, n, 1/k)*lcm([1..n])^2} \\ Andrew Howroyd, Jan 08 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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