%I #23 Nov 09 2019 03:11:09

%S 7,49,103,193,367,1003,20365,37447,56083

%N Numbers k such that (16*10^(k-1) - 61)/9 is a plateau 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, <a href="http://www.worldofnumbers.com/deplat.htm#pdp171">PDP Reference Table - 171</a>.

%H Makoto Kamada, <a href="https://stdkmd.net/nrr/1/17771.htm#prime">Prime numbers of the form 177...771</a>.

%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.

%F a(n) = A056248(n+1) + 2.

%e k=7 -> (16*10^(7-1) - 61)/9 = 1777771.

%Y Cf. A082697-A082720, A056248.

%K nonn,base,more

%O 1,1

%A _Patrick De Geest_, Apr 13 2003

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

%E Edited by _Ray Chandler_, Nov 04 2014