Column 4 of A142249.

Terms

a(0) =4a(1) =65a(2) =566a(3) =3710a(4) =20756a(5) =105299a(6) =500862a(7) =2278936a(8) =10046620a(9) =43280341a(10) =183278902a(11) =766153042a(12) =3171277460a(13) =13027450455a(14) =53203165950a(15) =216290270892a(16) =876183166140