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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

Amiram Eldar, Table of n, a(n) for n = 1..3321

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

Adjacent sequences:  A065565 A065566 A065567 * A065569 A065570 A065571

KEYWORD

nonn

AUTHOR

Wouter Meeussen, Nov 30 2001

STATUS

approved

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Last modified August 9 17:13 EDT 2022. Contains 356026 sequences. (Running on oeis4.)