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%I #32 Apr 03 2023 10:36:09
%S 3,313,31415926535897932384626433833462648323979853562951413
%N Palindromic primes formed from the reflected decimal expansion of Pi.
%C _Carlos Rivera_ reports that the next two members of this sequence have 301 and 921 digits. The first has been tested with APRTE-CLE. The second one is only a StrongPseudoPrime at the moment. - May 16 2003
%C Thomas Spahni reports that the fifth member of this sequence with 921 digits is prime. He used Francois Morain's ECPP-V6.4.5a which proved primality in 14913.7 seconds running on a Celeron Core2 CPU at 2.00GHz. - Jun 05 2008
%C Primes in A135697. Terms with an odd number of digits are the primes in A135698. - _Omar E. Pol_, Mar 06 2012
%H C. K. Caldwell and G. L. Honaker, Jr., Prime Curios!, <a href="https://t5k.org/curios/page.php?curio_id=725">31414...51413 (53-digits)</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PalindromicPrime.html">Palindromic Prime.</a>
%t Select[Table[p = Flatten[RealDigits[Pi, 10, d]]; (FromDigits[p] - 1)*10^(Length[p] - 3) + FromDigits[Drop[Reverse[p], 2]], {d, 27}], PrimeQ] (* _Arkadiusz Wesolowski_, Dec 18 2011 *)
%Y Cf. A002385, A119351, A135697, A135698.
%K base,nonn,bref
%O 1,1
%A _G. L. Honaker, Jr._
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