1274544128

Appears in sequences

• Apart from the leading term, a(n) = Catalan(n-1)*4^(n-1).at n=10A052704
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2*n steps taken from {(-1, 0), (-1, 1), (1, 0), (1, 1)}.at n=9A151403
• a(n) = 2^n*n!/((floor(n/2)+1)*floor(n/2)!^2).at n=18A240558