2*A197072(n-1) - A197072(n).

Terms

a(0) =-3a(1) =-3a(2) =-5a(3) =5a(4) =1a(5) =1a(6) =13a(7) =-71a(8) =47a(9) =97a(10) =-65a(11) =23a(12) =73a(13) =-149a(14) =719a(15) =-345a(16) =2453a(17) =299a(18) =1737a(19) =7851a(20) =5359a(21) =22021a(22) =30039a(23) =45211a(24) =143627a(25) =210871a(26) =404681a(27) =627271a(28) =1446107a(29) =2401465