You can do one of:
array<int> ^int_array = { 0x3, 0x9, 0x7 };
or:
int_array = gcnew array<int>(3) { 0x3, 0x9, 0x7 };
or:
array<int> ^int_array = gcnew array<int>(3) { 0x3, 0x9, 0x7 };

i.e., the value initializer must occur in the same statement as array
creation.