Number of 3D walks of type ace.

Terms

a(0) =1a(1) =3a(2) =11a(3) =44a(4) =188a(5) =842a(6) =3911a(7) =18692a(8) =91412a(9) =455540a(10) =2306028a(11) =11829424a(12) =61375408a(13) =321583108a(14) =1699500055a(15) =9049714852a(16) =48513809796a(17) =261638920412