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%I #30 Mar 26 2020 06:33:05
%S 3,17,19,705,1061,1395,2631,3837,5749,11753,13537,125877,269479
%N Numbers k such that (10^k - 1) - 7*10^floor(k/2) is a palindromic wing prime (a.k.a. near-repdigit palindromic prime).
%C Prime versus probable prime status and proofs are given in the author's table.
%D C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H Patrick De Geest, World!Of Numbers, <a href="http://www.worldofnumbers.com/wing.htm#pwp929">Palindromic Wing Primes (PWP's)</a>
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/9/99299.htm#prime">Prime numbers of the form 99...99299...99</a>
%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F a(n) = 2*A115073(n) + 1.
%e 17 is a term because (10^17 - 1) - 7*10^8 = 99999999299999999.
%t Do[ If[ PrimeQ[10^n - 7*10^Floor[n/2] - 1], Print[n]], {n, 3, 14600, 2}] (* _Robert G. Wilson v_, Dec 16 2005 *)
%Y Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187.
%K more,nonn,base
%O 1,1
%A _Patrick De Geest_, Nov 16 2002
%E Two more terms from PWP table added by _Patrick De Geest_, Nov 05 2014
%E Name corrected by _Jon E. Schoenfield_, Oct 31 2018
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