%I A123344
%S A123344 1,1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,
%T A123344 131072,262144,524288,1048576,2097152,4194304,8388608,16777216,33554432,
%U A123344 67108864,134217728,268435456,536870912,1073741824,2147483648
%V A123344 1,1,-2,4,-8,16,-32,64,-128,256,-512,1024,-2048,4096,-8192,16384,-32768,
               65536,-131072,
%W A123344 262144,-524288,1048576,-2097152,4194304,-8388608,16777216,-33554432,67108864,
%X A123344 -134217728,268435456,-536870912,1073741824,-2147483648
%N A123344 Expansion of (1+3x)/(1+2x).
%C A123344 Inverse binomial transform of A000034 . Hankel transform is [1,-3,0,0,
               0,0,0,0,0,0,...]
%F A123344 a(0)=1, a(n)=(-2)^(n-1) for n>0 .G.f.: (1+3x)/(1+2x).
%p A123344 a:=n->mul(-2, k=0..n): seq(a(n), n=-2..30); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Jan 22 2008
%Y A123344 Cf. A011782(unsigned version).
%Y A123344 Sequence in context: A166687 A011782 A034008 this_sequence A131577 A141531 
               A166444
%Y A123344 Adjacent sequences: A123341 A123342 A123343 this_sequence A123345 A123346 
               A123347
%K A123344 easy,sign
%O A123344 0,3
%A A123344 Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 11 2006