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

Terms

a(0) =6a(1) =33a(2) =168a(3) =816a(4) =3840a(5) =17664a(6) =79872a(7) =356352a(8) =1572864a(9) =6881280a(10) =29884416a(11) =128974848a(12) =553648128a(13) =2365587456a(14) =10066329600a(15) =42681237504a(16) =180388626432a(17) =760209211392