SEQUENCE statement
Standard: F77 F90 F95 F2003

The SEQUENCE statement may occur only in a derived type definition. It must precede all component definition statements.
The SEQUENCE statement declares a derived type to be a sequence type. Variables of a sequence type are permitted to appear in COMMON blocks. Also, two sequence types are considered to be the same type if their components have the same name, type, type parameters and appear in the same order.

Use of sequence types is not recommended, as they are less efficient and more error-prone than ordinary derived types.
Derived Type Definition