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A036303 Composite numbers n such that digits of prime factors of n are either 1 or 3. 3

%I

%S 9,27,33,39,81,93,99,117,121,143,169,243,279,297,339,341,351,363,393,

%T 403,429,507,729,837,891,933,939,961,993,1017,1023,1053,1089,1179,

%U 1209,1243,1287,1331,1441,1469,1521,1573,1703,1859,2187,2197,2511,2673,2799

%N Composite numbers n such that digits of prime factors of n are either 1 or 3.

%C All terms are a product of at least two terms of A020451. - _David A. Corneth_, Oct 09 2020

%H David A. Corneth, <a href="/A036303/b036303.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Alois P. Heinz)

%H <a href="/index/Pri#prime_factors">Index entries for sequences related to prime factors</a>

%e The composite 117 = 3^2 * 13 is in the sequence as the digits of the prime factors are either 1 or 3. - _David A. Corneth_, Oct 17 2020

%Y Cf. A003597, A036302-A036325.

%K nonn,easy,base

%O 1,1

%A _Patrick De Geest_, Dec 15 1998

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Last modified January 26 10:23 EST 2021. Contains 340438 sequences. (Running on oeis4.)