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Prime numbers p for which p1=base(p,9), p2=base(p1,8), p3=base(p2,7) and p4=base(p3,6) are prime, where base(N,b) means N written in base b and read in base 10.
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%I #9 Nov 12 2019 09:24:41

%S 2,3,5,136447,1555117,2520943,3085063,4517173,4755061,5761801,7991773,

%T 8997883,9057493,9193543,9672373,10964449

%N Prime numbers p for which p1=base(p,9), p2=base(p1,8), p3=base(p2,7) and p4=base(p3,6) are prime, where base(N,b) means N written in base b and read in base 10.

%C Sequence suggested by a question posed in the "primenumbers" group, cf. Link.

%H J. Brennen, in reply to J. Merickel, <a href="http://groups.yahoo.com/group/primenumbers/message/22932">Problem that should be solvable requiring scientific approach</a> on yahoo group "primenumbers", Aug 07 2011

%H James Merickel, Jack Brennen and others, <a href="/A193888/a193888.txt">Problem that should be solvable requiring scientific approach</a>, digest of 11 messages in primenumbers Yahoo group, Aug 6 - Aug 7, 2011.

%F A193888 = { prime(n) | A193889(n) < 6 }.

%K nonn

%O 1,1

%A _M. F. Hasler_, Aug 07 2011