p-INVERT of (1,2,2,2,2,2,2,...) (A040000), where p(S) = (1 - S)^2.

Terms

a(0) =2a(1) =7a(2) =20a(3) =57a(4) =158a(5) =431a(6) =1160a(7) =3089a(8) =8154a(9) =21367a(10) =55644a(11) =144137a(12) =371638a(13) =954335a(14) =2441872a(15) =6228129a(16) =15839794a(17) =40181095a(18) =101690404a(19) =256812121a(20) =647303502a(21) =1628647055a(22) =4091042328a(23) =10260849073a(24) =25699419914a(25) =64283165143a(26) =160599382124a(27) =400772669481a(28) =999059833190