Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (1, 1)}.
A151355
Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =2a(4) =4a(5) =14a(6) =45a(7) =120a(8) =468a(9) =1478a(10) =5208a(11) =18714a(12) =67200a(13) =244208a(14) =914953a(15) =3393606a(16) =12865732a(17) =48963934a(18) =187738332a(19) =724740954a(20) =2816697570a(21) =10990919138a(22) =43152034764a(23) =170075450764a(24) =673260699676
External references
- oeis: A151355