Expansion of cosh(3*arctanh(2*sqrt(x))).

Terms

a(0) =1a(1) =18a(2) =102a(3) =500a(4) =2310a(5) =10332a(6) =45276a(7) =195624a(8) =836550a(9) =3549260a(10) =14965236a(11) =62783448a(12) =262303132a(13) =1092063000a(14) =4533175800a(15) =18769219920a(16) =77539370310a(17) =319704052140