Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 0), (-1, 1), (0, -1), (1, -1), (1, 1)}.

A151449

Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 0), (-1, 1), (0, -1), (1, -1), (1, 1)}.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =4a(4) =18a(5) =46a(6) =214a(7) =742a(8) =3146a(9) =12162a(10) =51862a(11) =214090a(12) =921302a(13) =3937074a(14) =17192430a(15) =75188002a(16) =332778382a(17) =1478794218a(18) =6622770990a(19) =29791504178a(20) =134763557054a(21) =612115880722

External references