A129693 - OEIS

%I #17 Mar 26 2018 19:52:29

%S 2,3,5,7,19,23,29,31,47,53,67,71,173,179,211,263,269,281,283,431,479,

%T 607,641,643,647,1559,1613,1619,1901,1907,2371,2423,2531,2549,2551,

%U 3881,5471,5791,5827,14033,14519,17117,17167,21341,21347,22783,22787,22943

%N Right truncatable primes in base 9 (written in decimal form).

%C There are exactly 68 right truncatable primes in base 9.

%H Martin Renner, <a href="/A129693/b129693.txt">Table of n, a(n) for n = 1..68</a>

%H I. O. Angell, and H. J. Godwin, <a href="http://dx.doi.org/10.1090/S0025-5718-1977-0427213-2">On Truncatable Primes</a>, Math. Comput. 31, 265-267, 1977.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TruncatablePrime.html">Truncatable Prime</a>.

%H <a href="/index/Tri#tprime">Index entries for sequences related to truncatable primes</a>

%p Extend:= proc(n) op(select(isprime, [seq(9*n+k,k=1..8)])) end proc:

%p S:= {}: Agenda:= {2,3,5,7}:

%p while Agenda <> {} do

%p   S:= S union Agenda;

%p   Agenda:= map(Extend, Agenda);

%p od:

%p sort(convert(S,list)); # _Robert Israel_, Mar 25 2018

%Y Cf. A024769, A076586.

%K nonn,base,fini,full

%O 1,1

%A _Martin Renner_, Jun 01 2007