%I #14 Jul 06 2019 14:20:27
%S 11,0,0,0,0,3131313131313131313113,71717117,9191919191919119,0,
%T 32323223,0,9292929292929292929229,13131331,0,
%U 7373737373737373737373737373737373737373737337,0,14141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141441
%N Smallest prime which is the repeated reverse concatenation of n followed by n (ending in n), where n == 1,3,7 or 9 (mod 10), or 0 if no such prime exists.
%C Conjecture: a(n) is 0 iff n is a palindromic prime == 1,3,7 or 9 (mod 10) and/or n ==0 (mod 3). As rev(n) followed by n is == 0 (mod 11), hence every nonzero term contains at least two reverse concatenations of n followed by n.
%C The larger numbers are probable primes. - _Joshua Zucker_, May 10 2006
%C The Magma Calculator (http://magma.maths.usyd.edu.au/calc/) verified each of the nine nonzero terms as prime. - _Jon E. Schoenfield_, Aug 24 2009
%Y Cf. A110409.
%K base,easy,nonn
%O 0,1
%A _Amarnath Murthy_, Jul 30 2005
%E More terms from _Joshua Zucker_, May 10 2006
%E Edited by _T. D. Noe_, Oct 30 2008