Sum{T(n,k)*T(n,k+3)}, 0<=k<=2n-3, T given by A027926.

Terms

a(0) =16a(1) =70a(2) =292a(3) =1197a(4) =4864a(5) =19656a(6) =79124a(7) =317592a(8) =1271976a(9) =5085730a(10) =20307396a(11) =81003583a(12) =322847552a(13) =1285900570a(14) =5119076236a(15) =20370229878a(16) =81032093192a(17) =322258628220