Duplicate of A070428.

Terms

a(0) =1a(1) =4a(2) =13a(3) =41a(4) =125a(5) =367a(6) =1111a(7) =3395a(8) =10491a(9) =32670a(10) =102231a(11) =320990a(12) =1010196a(13) =3184138