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, 0), (0, 1, -1), (1, 0, 0), (1, 1, 1)}.
A150121
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, 0), (0, 1, -1), (1, 0, 0), (1, 1, 1)}.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =20a(4) =68a(5) =246a(6) =890a(7) =3282a(8) =12264a(9) =46038a(10) =174702a(11) =664952a(12) =2543250a(13) =9769374a(14) =37618194a(15) =145377752a(16) =562898688a(17) =2184186964a(18) =8492135236a(19) =33064770660a(20) =128960010734a(21) =503568004634
External references
- oeis: A150121