The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

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