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MAPLE
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b:= proc(n, i, j) option remember;
`if`(n<0 or i<0 or i>7 or j<0 or j>7, 0, `if`({n, i, j}={0},
1, add (add (b(n-1, i+t*r[1], j+t*r[2]), r=[[1, 1], [1, -1],
[-1, 1], [-1, -1]]), t=1..7)))
end:
a:= n-> b (n, 7, 7):
seq (a(n), n=0..30); # Alois P. Heinz, Jun 26 2012
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