OFFSET
1,5
MAPLE
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);
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Plus @@ (a /@ Select[Range[n/2], GCD[ #, n] == 1 &]); Table[ a[n], {n, 70}] (* Robert G. Wilson v, Dec 09 2004 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Dec 06 2004
EXTENSIONS
More terms from Emeric Deutsch and Robert G. Wilson v, Dec 09 2004
STATUS
approved