73 -> 2n+1 ever prime?

Christian G.Bower bowerc at usa.net
Sun Dec 19 09:43:11 CET 1999

I was looking at the EIS and found sequence A051914 where Neil was
seeking clarification. So I worked out what its meaning and that led
to the following computation.

Take 73 then iterate f(n)=2n+1 on the value to get

147 295 591 1183 ...

until I get a value that's prime.

So far I'm up to


without finding one.

Perhaps someone with a smart prime testing algorithm can do the search
or someone with some theoretical knowledge can tell me the search is
in vain.


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