

A211682


Prime numbers such that all the substrings of length <= 2 are primes.


54



2, 3, 5, 7, 23, 37, 53, 73, 373, 237373, 537373, 5373737, 53737373, 53737373737, 237373737373, 737373737373737, 53737373737373737, 373737373737373737373, 53737373737373737373737, 53737373737373737373737373, 373737373737373737373737373, 5373737373737373737373737373737
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OFFSET

1,1


COMMENTS

A211681 restricted to primes. Contains A085823. In contrast to A085823 this sequence seems to be not finite (conjecture).


LINKS



EXAMPLE

a(10)=237373, since all substrings of length <= 2 are primes (2, 3, 7, 23, 37, 73) and 237373 is prime.


CROSSREFS



KEYWORD

nonn,base


AUTHOR



EXTENSIONS

The originally submitted terms with index 20 and 21 are composite and have been erased therefore.  Hieronymus Fischer, Sep 24 2018


STATUS

approved



