A082706 - OEIS

%I #19 Nov 10 2019 01:32:57

%S 7,13,493,5569,24757

%N Numbers k such that (31*10^(k-1) - 13)/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#pdp343">PDP Reference Table - 343</a>.

%H Makoto Kamada, <a href="https://stdkmd.net/nrr/3/34443.htm#prime">Prime numbers of the form 344...443</a>.

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

%F a(n) = A056253(n) + 2.

%e k=13 -> (31*10^(13-1) - 13)/9 = 3444444444443.

%Y Cf. A082697-A082720, A056253.

%K nonn,base,hard,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 05 2014