p-INVERT of (1,1,0,0,0,0,...), where p(S) = 1 - 2 S - S^2 + S^3.

Terms

a(0) =2a(1) =7a(2) =21a(3) =63a(4) =189a(5) =567a(6) =1699a(7) =5092a(8) =15260a(9) =45731a(10) =137046a(11) =410697a(12) =1230768a(13) =3688339a(14) =11053134a(15) =33123790a(16) =99264648a(17) =297474121a(18) =891463923a(19) =2671519536a(20) =8005951162a(21) =23992058879a(22) =71898875923a(23) =215464974683a(24) =645700711159