Expansion of x(1-2x-2x^2)/((1+x)(1-2x)(1-3x)).

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =12a(5) =31a(6) =82a(7) =225a(8) =632a(9) =1811a(10) =5262a(11) =15445a(12) =45652a(13) =135591a(14) =404042a(15) =1206665a(16) =3609072a(17) =10805371a(18) =32372422a(19) =97029885a(20) =290914892a(21) =872395151a(22) =2616486402a(23) =7848061105a(24) =23541387112a(25) =70618568931a(26) =211844521982a(27) =635511196325