Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (1, 0, 1), (1, 1, -1)}.
A148721
Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (1, 0, 1), (1, 1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =7a(4) =25a(5) =68a(6) =256a(7) =786a(8) =3002a(9) =9819a(10) =38001a(11) =129307a(12) =505104a(13) =1767052a(14) =6941722a(15) =24794364a(16) =97776226a(17) =354776327a(18) =1403121352a(19) =5153640677a(20) =20427769985a(21) =75765814887a(22) =300824606403
External references
- oeis: A148721