A054093 T(n,n-1), array T as in A054090.
1, 2, 2, 8, 24, 106, 546, 3368, 24032, 195170, 1777650, 17950552, 199059672, 2405063018, 31448531954, 442501797656, 6666753146496, 107081325959938, 1826636018849442
Offset: 1
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