A026885 T(2n,n+3), T given by A026769.
1, 8, 46, 234, 1126, 5280, 24508, 113648, 529555, 2488742, 11824872, 56879504, 277155320, 1368080730, 6838288158, 34588110926, 176875174228, 913577365466, 4761373765578, 25015666670338, 132372375785294, 704914546281986
Offset: 3