991680

Appears in sequences

• a(n) = 412*n^6 - 408*n^5 - 1130*n^4 - 360*n^3 + 2368*n^2 - 912*n + 15*(1 - (-1)^n).at n=4A111112
• Number of self-avoiding planar walks of length 2n starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal.at n=10A284416