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, 1), (0, 1), (1, 0)}.
A151339
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, 1), (0, 1), (1, 0)}.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =2a(4) =2a(5) =0a(6) =16a(7) =44a(8) =28a(9) =192a(10) =934a(11) =1402a(12) =3476a(13) =20246a(14) =50790a(15) =99972a(16) =469618a(17) =1624064a(18) =3609582a(19) =12454800a(20) =49484974a(21) =133986816a(22) =389029068a(23) =1515899106a(24) =4833068324a(25) =13708903398a(26) =48687650964a(27) =170176839110a(28) =509652229334
External references
- oeis: A151339