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A212657
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Number of subsets of {1,2,...,n} with the sum of reciprocals <= 1.
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3
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1, 2, 3, 5, 8, 14, 26, 46, 83, 151, 276, 503, 921, 1689, 3113, 5730, 10549, 19441, 35868, 66209, 122316, 226157, 418373, 774394, 1434130, 2657246, 4925837, 9135444, 16949660, 31460444, 58415377, 108502932, 201604081, 374708242, 696650259, 1295562800, 2410001851, 4484208954, 8345621293
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OFFSET
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0,2
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COMMENTS
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The number of distinct sums of reciprocals is given by A212607.
a(n) grows as 2^(b*n) with b=0.911... (Tikhomirov et al. 2017).
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LINKS
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PROG
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(PARI) { A212657(n) = my(L=lcm(vector(n, i, i))); polcoeff( prod(i=1, n, 1+x^(L/i)+O(x^(L+1)) )/(1-x), L); }
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CROSSREFS
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Cf. A212658 (reciprocals can appear multiple times).
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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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