A026860 T(2n,n-3), T given by A026747.
1, 12, 95, 629, 3781, 21433, 116928, 621317, 3239925, 16662600, 84804868, 428176176, 2148404051, 10726889402, 53349600116, 264499086453, 1308025259637, 6455291067020, 31804649415803, 156486128169860, 769098411417361
Offset: 3