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A074225
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a(n) = n * Sum_{d|n} d*2^(d-1).
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1
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1, 10, 39, 148, 405, 1254, 3143, 8488, 20853, 52050, 123915, 297804, 692237, 1611974, 3687795, 8405584, 18939921, 42512562, 94634003, 209819940, 462431697, 1015269486, 2218786839, 4832458392, 10485762025, 22684180610, 48922424415, 105229923596
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OFFSET
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1,2
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LINKS
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Colin Barker, Table of n, a(n) for n = 1..1000
N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, arXiv:math/0307064 [math.CO], 2003.
N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, Order 21 (2004), 83-89.
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MATHEMATICA
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a[n_] := n*DivisorSum[n, #*2^(#-1)&]; Array[a, 30] (* Jean-François Alcover, Dec 03 2015 *)
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PROG
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(PARI) vector(100, n, n*sumdiv(n, d, d*2^(d-1))) \\ Colin Barker, Jan 29 2015
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CROSSREFS
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Equals n*A083413(n).
Sequence in context: A059722 A267748 A229325 * A055514 A055233 A267626
Adjacent sequences: A074222 A074223 A074224 * A074226 A074227 A074228
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Jun 15 2003
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STATUS
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approved
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