%I #2 Mar 30 2012 17:36:43

%S 1,0,-1,-1,-1,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,

%T 19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,

%U 42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,71,71,71,71,71,71,71,71

%N a(n) = a(n-1) - a(floor(sqrt(n))) for n > 1; a(1) = 1.

%F a(1)=1; a(n) = a(n-1) - a(floor(sqrt(n))) for n > 1.

%Y Cf. A097046 ( a(n-1) + a(floor(sqrt(n))) ).

%K sign

%O 1,11

%A _Rick L. Shepherd_, Jul 20 2004