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)}.
A151271
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) =9a(4) =32a(5) =92a(6) =324a(7) =1013a(8) =3612a(9) =11790a(10) =42448a(11) =142522a(12) =516780a(13) =1769552a(14) =6452240a(15) =22416043a(16) =82098940a(17) =288430178a(18) =1060206808a(19) =3757982994a(20) =13855171352a(21) =49467576888a(22) =182845418208a(23) =656756066722
External references
- oeis: A151271