

A102501


Primes of the concatenated form 7nn7.


3



715157, 718187, 719197, 734347, 736367, 739397, 748487, 752527, 757577, 760607, 767677, 775757, 779797, 781817, 785857, 796967, 797977, 7100510057, 7102010207, 7103010307, 7104710477, 7105410547, 7106210627, 7106510657, 7107410747
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OFFSET

1,1


LINKS



EXAMPLE

715157 is prime and of the form 7nn7 for n=15.
7100510057 is prime and of the form 7nn7 for n=1005.


CROSSREFS

Cf. A102897 for sequence of all numbers of form 7nn7. A102500 for the n values corresponding to the primes in this sequence.


KEYWORD

easy,nonn,base


AUTHOR

Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 13 2005


STATUS

approved



