%I #7 Mar 30 2012 17:38:11

%S 21,23,25,27,29,51,56,201,209,227,229,241,243,261,263,287,289,551,

%T 2023,2027,2043,2047,2061,2069,2081,2089,2207,2209,2221,2223,2263,

%U 2267,2281,2287,2401,2407,2421,2423,2441,2449,2483,2489,2603,2609

%N Primitive primes in carryless arithmetic mod 10.

%C Define the units in carryless arithmetic mod 10 to be the numbers 1, 3, 7 and 9 (these divide any number). A prime is a number N, not a unit, whose only factorizations are of the form N = u * M, where u is a unit.

%C A prime is primitive if it not the carryless product of a smaller prime and a unit.

%C A subsequence of A169887.

%H David Applegate, <a href="/A169903/b169903.txt">Table of n, a(n) for n = 1..843</a> (all primitive primes with <= 6 digits)

%H <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a>

%Y Cf. A004520, A059729, A168294, A168541, A169885, A169886, A169884, A169887.

%Y Cf. A058943, A058945.

%K nonn,base

%O 1,1

%A _David Applegate_, _Marc LeBrun_ and _N. J. A. Sloane_, Jul 11 2010