%I #9 Apr 16 2018 18:56:46
%S 1,-1,0,0,-1,0,0,0,0,0,-1,1,-1,-1,1,1,-1,-1,0,1,1,-3,1,4,-5,-3,3,4,2,
%T -6,-6,19,-8,-25,25,20,-12,-34,2,30,38,-117,54,159,-173,-123,55,229,
%U 32,-250,-148,753,-365,-1022,840,1121,-847,-1482,-390,2099
%N Solution to a(1) = 1 and Sum_y Product_i a(y_i) = 0 for each n > 1, where the sum is over all relatively prime or monic partitions of n.
%C A relatively prime or monic partition of n is an integer partition of n that is either of length 1 (monic) or whose parts have no common divisor other than 1 (relatively prime).
%t a[n_]:=a[n]=If[n===1,1,0]-Sum[Times@@a/@y,{y,Rest[Select[IntegerPartitions[n],Or[Length[#]===1,GCD@@#===1]&]]}];
%t Array[a,20]
%Y Cf. A000837, A036987, A047966, A063834, A093637, A196545, A220418, A289501, A290261, A300486, A300863-A300866, A301462, A302094, A302915, A302916.
%K sign
%O 1,22
%A _Gus Wiseman_, Apr 15 2018