%I A077784
%S A077784 3,5,35,159,237,325,355,371,481,1649,3641,4709
%N A077784 Palindromic wing primes (a.k.a. near-repdigit palindromes) of the form 
               (10^a(n)-1)/3+2*10^[ a(n)/2 ].
%C A077784 Prime versus probable prime status and proofs are given in the author's 
               table.
%D A077784 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 
               28, No. 1, 1996-97, pp. 1-9.
%H A077784 Patrick De Geest, World!Of Numbers, <a href="http://www.worldofnumbers.com/
               wing.htm#pwp353">Palindromic Wing Primes (PWP's)</a>
%H A077784 Makoto Kamada, <a href="http://homepage2.nifty.com/m_kamada/math/33533.htm">
               Factorizations of 33...33533...33</a>
%e A077784 a(n)=5 -> (10^5-1)/3+2*10^2 = 33533.
%t A077784 Do[ If[ PrimeQ[(10^n + 6*10^Floor[n/2] - 1)/3], Print[n]], {n, 3, 4800, 
               2}] (from Robert G. Wilson v (rgwv(at)rgwv.com), Dec 16 2005)
%Y A077784 Partial sums of S(n, x), for x=1...9: A021823, A000217, A027941, A061278, 
               A089817, A053142, A092521, A076765, A092420.
%Y A077784 Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A114633-A114647.
%Y A077784 Sequence in context: A001790 A057908 A120828 this_sequence A145640 A086158 
               A158878
%Y A077784 Adjacent sequences: A077781 A077782 A077783 this_sequence A077785 A077786 
               A077787
%K A077784 nonn
%O A077784 1,1
%A A077784 Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 16 2002.