How can all different graphs be made following these rules?

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Imagine a number $n$ of vertices. How many different graphs can be constructed given the following rules:

  1. No segment of the graph can be disconnected, this means there must be a path between any pair of vertices.
  2. All connections must be directed with an arrow.
  3. A vertex with no inputs has a value of 1.
  4. If two vertex are connected, the consequent one must have a bigger value than the first one. (This also means there cannot be any cycles)
  5. If there is a path moving only forward between two vertices, there cannot be a direct shortcut connection between them.

Is there an algorithm I can use to make sure I have count them all?