Number of 3D walks of type abe.

Terms

a(0) =1a(1) =2a(2) =7a(3) =26a(4) =108a(5) =472a(6) =2159a(7) =10194a(8) =49396a(9) =244328a(10) =1229308a(11) =6273896a(12) =32410096a(13) =169181664a(14) =891181607a(15) =4731912082a(16) =25302648644a(17) =136150941064a(18) =736747902236