%I A100677
%S A100677 1,1,1,1,2,1,3,2,3,2,6,3,7,4,6,7,12,6,15,8,9,10,23,12,22,16,25,20,37,17,
%T A100677 43,29,30,29,45,31,68,41,56,48,91,43,100,59,69,65,133,69,129,80,114,103,
%U A100677 183,91,152,123,147,135,265,104,282,172,215,215,274,165,384,233,277,203
%N A100677 a(1) = 1; a(n) = sum{1<=k<=n/2, GCD(k,n)=1} a(k).
%H A100677 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%p A100677 a[1]:=1: for n from 2 to 74 do b:=0: for k from 1 to n/2 do if gcd(k,
               n)=1 then b:=b+a[k] else b:=b fi od: a[n]:=b: od: seq(a[n],n=1..74);
%t A100677 a[1] = 1; a[n_] := a[n] = Plus @@ (a /@ Select[Range[n/2], GCD[ #, n] 
               == 1 &]); Table[ a[n], {n, 70}] (from Robert G. Wilson v Dec 09 2004)
%Y A100677 Sequence in context: A104481 A078709 A023022 this_sequence A083290 A121842 
               A087825
%Y A100677 Adjacent sequences: A100674 A100675 A100676 this_sequence A100678 A100679 
               A100680
%K A100677 nonn
%O A100677 1,5
%A A100677 Leroy Quet Dec 06 2004
%E A100677 More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu) and Robert 
               G. Wilson v, Dec 09 2004