Why is the 4p to 3s Transition Not Allowed in the Grotrian Diagram for Hydrogen?

[QuarkDecay]

Why is it that in Grotrian diagram only the 4p->3s is not allowed, but the 4s->3p, 4p-> 3d and 4d-> 3p are allowed ? I'm following the rules of Δl=±1 and Δm=0,±1 and they give the same numbers. I also tried with Δj=0,±1 and still the same.

Grotrian Diagram for Hydrogen for n=[1,4];
https://commons.wikimedia.org/wiki/File:Grotrian_H.svg#/media/File:Grotrian_H.svg

 

[DrClaude]

The diagram is in error. The 4p->3s is allowed and should be present.

 

[QuarkDecay]

Both my physics books and the ones I've seen on the internet have it like this though

 

[Lord Jestocost]

Maybe, the "NIST Atomic Spectra Database Lines Form" might be of help: https://physics.nist.gov/PhysRefData/ASD/lines_form.html