This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A077782 #31 Mar 26 2020 06:38:34
%S A077782 29,45,73,209,2273,35729,50897
%N A077782 Numbers k such that (10^k - 1) - 5*10^floor(m/2) is a palindromic wing prime (a.k.a. near-repdigit palindromic prime).
%C A077782 Prime versus probable prime status and proofs are given in the author's table.
%D A077782 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H A077782 Patrick De Geest, World!Of Numbers, <a href="http://www.worldofnumbers.com/wing.htm#pwp949">Palindromic Wing Primes (PWP's)</a>
%H A077782 Makoto Kamada, <a href="https://stdkmd.net/nrr/9/99499.htm#prime">Prime numbers of the form 99...99499...99</a>
%H A077782 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F A077782 a(n) = 2*A183185(n) + 1.
%e A077782 29 is a term because (10^29 - 1) - 5*10^14 = 99999999999999499999999999999.
%t A077782 Do[ If[ PrimeQ[10^n - 5*10^Floor[n/2] - 1], Print[n]], {n, 3, 50900, 2}] (* _Robert G. Wilson v_, Dec 16 2005 *)
%Y A077782 Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187.
%K A077782 more,nonn,base
%O A077782 1,1
%A A077782 _Patrick De Geest_, Nov 16 2002
%E A077782 Name corrected by _Jon E. Schoenfield_, Oct 31 2018