OFFSET
1,2
EXAMPLE
The positive integers which are <= 12 and are not coprime to 12 are 2,3,4,6,8,9,10,12. And a(12) is such that a(2)+a(3)+a(4)+a(6)+a(8)+a(9)+a(10)+a(12) = 12.
MATHEMATICA
f[n_] := Select[Range[2, n], GCD[ #, n] > 1 &]; g[l_] := Block[{n = Length[l] + 1}, Append[l, n - Plus @@ l[[Most[f[n]]]]]]; Nest[g, {1}, 70] (* Ray Chandler, Nov 13 2006 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Leroy Quet, Oct 29 2006
EXTENSIONS
Extended by Ray Chandler, Nov 13 2006
STATUS
approved