%I A052089
%S A052089 43,109,2221,2423,3433,4241,5857,7069,7877,8887,10099,102101,108107,
%T A052089 112111,114113,124123,148147,154153,160159,172171,180179,192191,198197,
%U A052089 202201,208207,210209,214213,238237,244243,262261,264263,268267,270269
%N A052089 Primes formed by concatenating n with n-1.
%e A052089 2423 is a prime and a concatenation of 24 and 23.
%Y A052089 Cf. A030458, A052087, A052088.
%Y A052089 Sequence in context: A139969 A142055 A068699 this_sequence A039471 A104783 
               A142081
%Y A052089 Adjacent sequences: A052086 A052087 A052088 this_sequence A052090 A052091 
               A052092
%K A052089 nonn,base
%O A052089 1,1
%A A052089 Patrick De Geest (pdg(AT)worldofnumbers.com), Jan 15 2000.