%I #14 Oct 31 2019 01:24:04
%S 3,5,21,27,95,2075,2165,3047,3503,16791,34883
%N Numbers k such that the smoothly undulating palindromic number (78*10^k - 87)/99 is a prime.
%C Prime versus probable prime status and proofs are given in the author's table.
%C No further terms < 100000. - _Ray Chandler_, Aug 17 2011
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/undulat.htm#supp787">SUPP Reference Table - 787</a>
%H <a href="/index/Pri#pri_supp">Index entries for sequences related to smoothly undulating palindromic primes</a>
%e k=21 -> (78*10^21 - 87)/99 = 787878787878787878787.
%Y Cf. A062209-A062232, A059758, A032758.
%K nonn,base,more
%O 1,1
%A _Patrick De Geest_ and Hans Rosenthal (Hans.Rosenthal(AT)t-online.de), Jun 15 2001
%E Edited by _Ray Chandler_, Aug 17 2011