Number of paths from (0,0) to (n,2), with vertices (i,k) satisfying 0 <= k <= 3, consisting of segments given by the vectors (1,1), (1,2), (1,-1).
A247325
Number of paths from (0,0) to (n,2), with vertices (i,k) satisfying 0 <= k <= 3, consisting of segments given by the vectors (1,1), (1,2), (1,-1).
Terms
- a(0) =0a(1) =1a(2) =1a(3) =4a(4) =5a(5) =13a(6) =22a(7) =45a(8) =87a(9) =166a(10) =329a(11) =627a(12) =1232a(13) =2373a(14) =4621a(15) =8956a(16) =17377a(17) =33737a(18) =65422a(19) =127009a(20) =246363a(21) =478134a(22) =927685a(23) =1800119a(24) =3492960a(25) =6777593a(26) =13151433a(27) =25518580a(28) =49516525a(29) =96081013
External references
- oeis: A247325