%I M3079 #22 Apr 10 2016 15:16:26
%S 1,3,21,23,842,1683,3401,16839,49963,60239,150940,155928
%N n*18^n + 1 is a prime.
%C a(13) > 203597. - _Ray Chandler_, Apr 10 2016
%D H. Dubner, Generalized Cullen numbers, J. Rec. Math., 21 (No. 3, 1989), 190-191.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%t k = 0; While[k < 10001, If[PrimeQ[k*18^k + 1], Print@ k]; k++] (* _Robert G. Wilson v_, Aug 19 2013 *)
%K nonn,hard
%O 1,2
%A _N. J. A. Sloane_.
%E Error in description corrected 8/97.
%E a(7) from _Robert G. Wilson v_, Dec 10 2012
%E a(8)-a(10) from _Giovanni Resta_, Aug 21 2013
%E a(11)-a(12) from Loeh link by _Ray Chandler_, Apr 10 2016