%I #7 Dec 05 2013 19:56:37
%S 2,7,3,33,9,77,33,999,1111111,3,33,777777,111111111,77,333333,111,
%T 99999999,3333333333,777777,1,33333333333333333333,
%U 999999999999999999999999999999999999,99999999,999999999999999999999999999999999999999999,3333333333333333333333333
%N Least number with identical digits such that the concatenation a(n) a(n-1) ...a(2)a(1) a(2) ... a(n-1) a(n) is a prime.
%C The resulting primes are given in A090275.
%e 2,727,37273,... etc. are primes.
%Y Cf. A090275.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 28 2003
%E More terms from _Sam Alexander_, Jan 06 2005
%E Many further terms from _David Wasserman_, Oct 27 2005