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A007648 n*18^n + 1 is a prime.
(Formerly M3079)
3

%I M3079

%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

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Last modified May 24 18:27 EDT 2022. Contains 354043 sequences. (Running on oeis4.)