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A065568 Sum over all subsets of {1,..,n} of the GCD of the subset. 3
1, 4, 10, 22, 42, 84, 154, 298, 568, 1108, 2142, 4254, 8362, 16636, 33076, 66004, 131556, 262974, 525136, 1050016, 2098756, 4196962, 8391288, 16782312, 33559612, 67118176, 134227594, 268453714, 536889198, 1073777718, 2147519572 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
MATHEMATICA
Sum[Plus @@ GCD @@@ KSubsets[Range[n], m], {m, n}] (* or *)
Table[Sum[Plus@@(EulerPhi[Divisors[k]] 2^(k/Divisors[k]))/2, {k, n}], {n, 42}]
CROSSREFS
Row sums of A065567, first differences equal A034738,
Sequence in context: A055364 A284870 A032191 * A007825 A008256 A006001
KEYWORD
nonn
AUTHOR
Wouter Meeussen, Nov 30 2001
STATUS
approved

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Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)