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Semiprimes (A001358) made of nontrivial runs of identical digits.
1

%I #2 Mar 30 2012 17:40:36

%S 22,33,55,77,111,1111,1133,1177,1199,3377,4411,4499,5533,5599,6611,

%T 6677,7711,7799,8899,9977,11111,11199,11333,11555,22233,22255,22299,

%U 22333,22999,33322,44222,44333,44411,44477,44999,55111,55222,55577

%N Semiprimes (A001358) made of nontrivial runs of identical digits.

%C A run of length 1 is trivial.

%e 44477 = 79*563

%Y Cf. A001358, A033023, A116062.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 13 2006