a(n) = (3*2^(n-1)-1)*(18*2^(n-1)-7).

Terms

a(0) =1a(1) =22a(2) =145a(3) =715a(4) =3151a(5) =13207a(6) =54055a(7) =218695a(8) =879751a(9) =3528967a(10) =14135815a(11) =56583175a(12) =226412551a(13) =905809927a(14) =3623559175a(15) =14494875655a(16) =57980780551a(17) =231925678087a(18) =927707824135