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%I #3 Mar 31 2012 10:26:15
%S 19,199,1999,1999999999999999999999999999
%N Invertible primes of the form 1 followed by a string of 9's.
%C These are values in A055558 whose rotation by 180 degrees occurs in A092571. I have checked all the numbers that correspond to entries in A002957 and can confirm that the next term in this sequence, if it exists, is greater than 2*10^55347-1. [From _Dmitry Kamenetsky_, May 22 2009]
%e 1999, for instance, is a prime which rotated upside down through 180 degrees becomes the prime 6661. Hence 1999 is in the sequence.
%Y Cf. A048890, A055558.
%Y Cf. A092571, A002957. [From _Dmitry Kamenetsky_, May 22 2009]
%K more,nonn,base
%O 1,1
%A _Lekraj Beedassy_, May 14 2009
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