A065568 Sum over all subsets of {1,..,n} of the GCD of the subset.

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

Offset: 1

Author

Wouter Meeussen, Nov 30 2001

Keywords

• nonn

Links

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

Crossrefs

Row sums of A065567, first differences equal A034738,

Programs

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}]