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 A085831 Sum_{k=1..2^n} d(k) where d(n) = number of divisors of n (A000005). 6
 1, 3, 8, 20, 50, 119, 280, 645, 1466, 3280, 7262, 15937, 34720, 75108, 161552, 345785, 736974, 1564762, 3311206, 6985780, 14698342, 30850276, 64607782, 135030018, 281689074, 586636098, 1219788256, 2532608855, 5251282902, 10874696106, 22493653324, 46475828418 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Donovan Johnson, Table of n, a(n) for n = 0..64 MATHEMATICA k = s = 0; Do[ While[ k < 2^n, k++; s = s + DivisorSigma[ 0, k ]]; Print[s], {n, 0, 29} ] CROSSREFS Cf. A006218, A050226, A085567, A085829, A057494. Sequence in context: A093963 A261233 A027219 * A178167 A078053 A122595 Adjacent sequences:  A085828 A085829 A085830 * A085832 A085833 A085834 KEYWORD nonn AUTHOR Robert G. Wilson v, Sep 21 2000 STATUS approved

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Last modified July 19 08:12 EDT 2019. Contains 325155 sequences. (Running on oeis4.)