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A140651
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A140579^(-1) * A000290, the squares starting (1, 4, 9, ...).
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1
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1, 2, 3, 8, 5, 36, 7, 32, 27, 100, 11, 144, 13, 196, 225, 128, 17, 324, 19, 400, 441, 484, 23, 576, 125, 676, 243, 784, 29, 900, 31, 512, 1089, 1156, 1225, 1296, 37, 1444, 1521, 1600, 41, 1764, 43, 1936, 2025, 2116, 47, 2304, 343, 2500, 2601, 2704, 53, 2916, 3025, 3136, 3249, 3364, 59, 3600
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OFFSET
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1,2
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COMMENTS
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For n > 1, a(n) = n iff n is prime.
a(n) is n times the least common multiple of the proper divisors of n, a(n) = n*A048671(n). - Peter Luschny, Jun 22 2011
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LINKS
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FORMULA
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A140579^(-1) * (1, 4, 9, 16, 25, ...).
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EXAMPLE
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A140579 = an infinite lower triangular matrix with A014963 in the main diagonal and the rest zeros; where A014963 = (1, 2, 3, 2, 5, 1, 7, ...).
a(5) = 5 = (1/A014963(5)) * 25 = (1/5)*25.
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MAPLE
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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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