A026575 T(2n,n-1), T given by A026568.
1, 2, 12, 38, 200, 701, 3682, 13294, 70665, 258430, 1388002, 5114572, 27682135, 102539204, 558172494, 2075658454, 11348521989, 42330184638
Offset: 1
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