A026574 T(2n,n), T given by A026568.
1, 1, 7, 19, 103, 341, 1809, 6336, 33899, 121483, 656199, 2381512, 12957809, 47419503, 259395664, 954961034, 5245001951, 19397198595, 106871608053
Offset: 0
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