Sum of products of terms in all partitions of 3*n into powers of 3.

Terms

a(0) =1a(1) =4a(2) =13a(3) =49a(4) =157a(5) =481a(6) =1534a(7) =4693a(8) =14170a(9) =43357a(10) =130918a(11) =393601a(12) =1188454a(13) =3573013a(14) =10726690a(15) =32248957a(16) =96815758a(17) =290516161a(18) =872169223a(19) =2617128409a(20) =7852005967a(21) =23561605318a(22) =70690403371a(23) =212076797530a(24) =636280680100