Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 1), (-1, 0), (1, -1), (1, 1)}.
A151273
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 1), (-1, 0), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =11a(4) =42a(5) =130a(6) =506a(7) =1701a(8) =6678a(9) =23348a(10) =92162a(11) =330718a(12) =1310042a(13) =4785834a(14) =19002354a(15) =70329169a(16) =279708134a(17) =1045513784a(18) =4163154786a(19) =15682361864a(20) =62502107274a(21) =236910288210a(22) =944854095762
External references
- oeis: A151273