A026874 T(2n,n+3), T given by A026758.
1, 8, 46, 233, 1109, 5102, 23020, 102718, 455608, 2015496, 8912244, 39452385, 175026904, 778762339, 3476922430, 15581908258, 70108401416, 316728595048, 1436752952543, 6543920192177, 29923907812601, 137363507432013, 632899405886519
Offset: 3